Herbal Monograph
Senna
Senna alexandrina Mill.
Fabaceae (Leguminosae)
The world's most widely used herbal laxative -- an ancient Arabian remedy now standardized in modern pharmacopeias worldwide.
Overview
Plant Description
Small, erect, branching shrub or subshrub, 0.5-1 m tall (occasionally to 2 m). Stems pale green, smooth, becoming woody at the base. Leaves alternate, paripinnately compound, 8-12 cm long, with 4-8 pairs of leaflets. Leaflets lanceolate to ovate-lanceolate (Alexandrian senna) or narrowly lanceolate (Tinnevelly senna), 2-6 cm long, 0.7-2 cm wide, acute at apex, asymmetric at base, entire-margined, pale grayish-green, glabrous or with fine appressed hairs on both surfaces, with a characteristic papery texture when dried. Venation pinnate with prominent midrib. Inflorescence an axillary raceme with bright yellow flowers, each 2-3 cm in diameter, with 5 unequal petals prominently veined with darker yellow or brown. Stamens 10, with 3 large curved lower stamens. Fruit a flat, broadly oblong, papery, indehiscent legume (pod), 4-7 cm long, 1.5-2.5 cm wide, dark brown when mature, containing 6-8 flat, obcordate seeds. Both the dried leaflets and dried pods (fruits) are used medicinally, with the pods considered slightly milder in action than the leaves.
Habitat
Native to arid and semi-arid regions of North Africa and the Arabian Peninsula. Thrives in hot, dry climates with well-drained sandy or loamy soils. Tolerates poor soil and drought conditions. Requires full sun. Temperature range 25-35C optimal. Does not tolerate frost or waterlogging. Grows from sea level to approximately 1000 m altitude in its native range.
Distribution
Two principal trade varieties based on geographic origin: Alexandrian senna (C. senna sensu stricto / C. acutifolia) from the Nile Valley region of Egypt and Sudan (historically exported through the port of Alexandria); and Tinnevelly senna (C. angustifolia) from southern India (Tamil Nadu, particularly the Tirunelveli/Tinnevelly district) and Pakistan. Now cultivated commercially in India (largest producer), Sudan, Egypt, Pakistan, Somalia, Saudi Arabia, and parts of China. India dominates global production, with Rajasthan and Tamil Nadu as primary growing regions. Wild populations occur across the Sahel region of Africa.
Parts Used
Dried leaflets (Sennae folium)
Preferred: Standardized powdered leaf extract (tablets/capsules), dried leaf for infusion, standardized liquid extracts
The primary officinal form in European, British, and Indian pharmacopeias. Alexandrian senna leaves (from Egyptian/Sudanese plants) are broader and considered slightly more potent, while Tinnevelly senna leaves (from Indian plants) are narrower and slightly milder but more consistently graded. Both are pharmacopeially equivalent. Leaves contain higher total sennoside content than pods. European Pharmacopoeia specifies minimum 2.5% hydroxyanthracene glycosides calculated as sennoside B. Leaves are the standard form for most commercial senna preparations worldwide.
Dried fruit/pods (Sennae fructus)
Preferred: Dried pods for infusion, standardized pod extracts
The dried ripe pods (fruits) of senna. Considered to produce fewer griping/cramping side effects compared to the leaf, making them preferable for some patients. European Pharmacopoeia specifies minimum 2.2% hydroxyanthracene glycosides calculated as sennoside B for pods. Alexandrian senna pods are broader and flatter; Tinnevelly senna pods are narrower and more elongated. The gentler action of pods is attributed to a lower concentration of free anthraquinone aglycones (which are more irritating) relative to the glycoside forms.
Key Constituents
Dianthrone glycosides (sennosides)
Sennosides A and B are the principal active compounds and are responsible for senna's stimulant laxative effect. They act as prodrugs: unabsorbed in the small intestine, they pass intact to the colon where bacterial enzymes (beta-glucosidases) cleave the sugar moieties to release rhein anthrone, the active metabolite. Rhein anthrone has two mechanisms: (1) it stimulates colonic myenteric plexus neurons (Auerbach's plexus) to increase peristalsis, and (2) it inhibits water and electrolyte absorption from the colonic lumen while promoting fluid and electrolyte secretion into the lumen, softening stool. This dual mechanism produces effective laxation typically within 6-12 hours of oral administration.
Anthraquinone glycosides (monomeric)
Monomeric anthraquinone glycosides contribute to overall laxative activity but are secondary to the dianthrone sennosides. Free aglycones (rhein, aloe-emodin, chrysophanol) are present in trace amounts in properly prepared senna and are more likely to cause griping/cramping than the glycoside forms. Higher proportions of free aglycones (from degraded or improperly stored material) are associated with more adverse effects and lower quality.
Naphthalene glycosides
Naphthalene glycosides are characteristic minor constituents of senna. Their contribution to therapeutic activity is considered secondary. They serve as useful chemotaxonomic markers for authentication of senna leaf material.
Flavonoids
Flavonoids in senna are secondary constituents that do not contribute to the primary laxative action but provide antioxidant and mild anti-inflammatory activity. They may contribute to the overall tolerability profile of whole-leaf preparations compared to isolated sennoside preparations.
Other constituents
Minor constituents provide supporting roles. Mucilage may moderate GI irritation from anthraquinones. Phytosterols and salicylic acid contribute minor anti-inflammatory effects. These compounds are part of the whole-plant matrix that distinguishes crude senna preparations from isolated sennoside products.
Herbal Actions
The defining and most potent action of senna. Sennosides act as prodrugs that are activated by colonic bacteria to release rhein anthrone, which stimulates peristalsis via the myenteric plexus (Auerbach's plexus) and promotes fluid and electrolyte secretion into the colonic lumen while inhibiting water reabsorption. This dual mechanism -- prokinetic and prosecretory -- produces effective laxation typically within 6-12 hours of oral administration. Senna is classified by the WHO, European Pharmacopoeia, and all major pharmacopeias as a stimulant (contact) laxative. It is one of the most widely used laxatives globally, included in the WHO Model List of Essential Medicines. IMPORTANT: Intended for short-term use only (maximum 1-2 weeks without medical supervision). Chronic use can lead to tolerance, dependency, melanosis coli, and electrolyte depletion.
[1, 2, 4]Reduces inflammation
Rhein and other anthraquinone aglycones demonstrate anti-inflammatory activity through inhibition of NF-kB signaling, COX-2 expression, and pro-inflammatory cytokine production in in vitro and animal studies. Flavonoid constituents (kaempferol, isorhamnetin) contribute additional anti-inflammatory effects. However, this action is secondary to the laxative use and is not the primary clinical reason for prescribing senna. The anti-inflammatory activity of rhein has been investigated in the context of conditions such as rheumatoid arthritis and nephropathy, but these are not established clinical indications for senna leaf.
[11]Prevents or slows oxidative damage to cells
Senna leaf extracts demonstrate free radical scavenging activity in in vitro assays, attributable primarily to flavonoid constituents (kaempferol, isorhamnetin) and to some extent the anthraquinone compounds. Antioxidant activity is a supplementary pharmacological property and is not a primary clinical use.
[11]Kills or inhibits the growth of microorganisms
In vitro studies demonstrate antibacterial and antifungal activity of senna leaf extracts and isolated anthraquinones against various organisms including Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Candida albicans. Rhein and aloe-emodin show the strongest antimicrobial activity among the anthraquinone constituents. Clinical significance at normal therapeutic laxative doses is not established. Antimicrobial activity is not a primary indication for senna.
[11]Therapeutic Indications
Digestive System
Acute constipation (short-term relief)
The primary and most well-supported indication for senna. WHO, European Pharmacopoeia, German Commission E, British Pharmacopoeia, and the US FDA (as an OTC laxative) all recognize senna for short-term relief of occasional constipation. Effective in 6-12 hours when taken orally at bedtime. Standard dose: 15-30 mg sennosides (calculated as sennoside B) for adults. Senna is one of the most commonly used laxatives worldwide and is included in the WHO Model List of Essential Medicines. CRITICAL: Short-term use only (1-2 weeks maximum without medical supervision). Investigation of underlying cause of constipation is warranted if symptoms persist.
[1, 2, 4]Bowel preparation before colonoscopy, radiological examination, or surgery
Senna is widely used in bowel cleansing regimens prior to colonoscopy and abdominal surgery. Typically used as part of a combined preparation with polyethylene glycol (PEG) solution. Multiple RCTs have compared senna-containing bowel prep regimens with other methods. Senna combined with PEG has shown comparable or improved bowel cleanliness versus PEG alone in several studies, with the advantage of reduced volume of PEG solution required, improving patient compliance. The American Society for Gastrointestinal Endoscopy recognizes senna-containing preparations as acceptable bowel preparation options.
[2, 7]Opioid-induced constipation
Senna is one of the most commonly recommended first-line treatments for opioid-induced constipation (OIC) in palliative care and chronic pain management guidelines. Multiple palliative care guidelines recommend senna (often combined with a stool softener such as docusate sodium) as first-line prophylaxis for OIC. Opioid medications slow colonic transit and increase water absorption, directly counteracting both mechanisms addressed by senna's activity. Dose may need to be higher than for functional constipation and may be used for longer periods under medical supervision in this context.
[4, 8]Constipation in pregnancy (under medical supervision)
Senna is classified as FDA Pregnancy Category C. It has been used traditionally and in clinical practice for constipation in pregnancy when dietary and lifestyle measures are insufficient. Limited amount of sennoside metabolites cross into breast milk. The Norwegian Mother and Child Cohort Study (2018) found no increased risk of malformations with senna use in pregnancy. However, senna should only be used in pregnancy under medical supervision and when milder measures (dietary fiber, adequate hydration, bulk-forming laxatives) have failed. Avoid in the first trimester if possible. Prefer the mildest effective dose for the shortest duration.
[4, 10]Constipation in elderly patients (short-term)
Commonly used for constipation in elderly and hospitalized patients. Agra et al. 1998 RCT in hospitalized elderly patients found senna-fiber combination effective for constipation management. However, elderly patients are more susceptible to electrolyte imbalances (particularly hypokalemia) and dehydration from stimulant laxative use. Use lowest effective dose, ensure adequate hydration, and monitor electrolytes with extended use. Chronic use should be avoided.
[9]Energetics
Temperature
cold
Moisture
dry
Taste
Tissue States
hot/excitation, damp/stagnation
In Unani (Greco-Islamic) medicine, senna is classified as hot in the first degree and dry in the second degree, though Western energetic frameworks generally classify it as cooling due to its bitter taste and cathartic, descending, eliminative action. In Ayurveda, senna (known as swarnapatri or sanay) is classified as having a bitter and sweet taste (rasa), a pungent post-digestive taste (vipaka), and hot potency (ushna virya). It pacifies vata and kapha but may aggravate pitta in excess. The bitter taste reflects its strong eliminative, downward-moving action on the bowels. Despite some traditional classifications as warming (due to its strong stimulating action on the colon), the net effect in Western energetic terms is cooling and drying -- it forcefully moves accumulation and stagnation downward and out. It is indicated for conditions of stagnation and accumulation in the lower bowel. Energetically, senna is a powerful mover, not a tonic; it should not be used to build or nourish, only to clear and eliminate.
Traditional Uses
Arabian/Unani Medicine
- Purgative for constipation and bowel cleansing (primary use since 9th century)
- Treatment of skin diseases and conditions of 'impure blood' (elimination through the bowels)
- Fever management (purgative therapy to eliminate morbid humors)
- Treatment of bilious conditions and liver congestion
- Component of compound purgative formulations
"Senna was first described therapeutically in Arabic medical literature in the 9th century CE. The physician Yuhanna ibn Masawaih (d. 857 CE) and later al-Tamimi (10th century) documented its use as a purgative. Senna became one of the most important drugs of Arabian pharmacy. It was introduced to European medicine by Arab traders and physicians during the Middle Ages, arriving in Europe through the spice trade routes. The name 'senna' itself derives from the Arabic 'sana' or 'sena'. Alexandrian senna takes its name from the Egyptian port through which it was historically exported to Europe. The great Islamic physician Serapion the Younger (Ibn Sarabi, 12th century) wrote extensively on senna's purgative properties."
[2]
Ayurveda
- Swarnapatri (golden leaf): Purgative for constipation and bowel cleansing
- Treatment of skin diseases (kushtha) by clearing ama (metabolic waste) through purgation
- Component of virechana (therapeutic purgation) protocols in Panchakarma detoxification
- Treatment of abdominal distension and flatulence
- Fever management through elimination
- Combined with carminatives (ginger, fennel) to reduce griping
"Senna is described in Ayurvedic texts as swarnapatri or sanay (from the Arabic). It is classified as having bitter-sweet taste (tikta-madhura rasa), hot potency (ushna virya), and pungent post-digestive effect (katu vipaka). It is considered a powerful rechana (laxative/purgative) that targets purishadhara kala (the membrane supporting fecal formation). In Panchakarma practice, senna may be used as part of virechana (therapeutic purgation) protocols. Ayurvedic practitioners typically combine senna with carminative herbs such as ginger, fennel, or coriander to mitigate the griping tendency of the anthraquinones. The Ayurvedic Pharmacopoeia of India includes senna leaf monographs."
Traditional African Medicine
- Purgative and laxative for constipation
- Treatment of intestinal worms (anthelmintic use)
- Skin conditions and dermatoses (internal cleansing)
- Treatment of gonorrhea and urinary conditions (ethnobotanical reports)
- Leaf decoction for fever and malaria (in some East African traditions)
"In the native range of senna across North and East Africa, the plant has a long history of use in traditional medicine. In Sudanese and Egyptian folk medicine, senna has been used as a purgative for centuries. In various East African traditional systems, the leaves and pods are used for constipation, intestinal parasites, and skin diseases. The plant is also used in some African traditions as a fever remedy, though this use is secondary to its purgative application. The widespread availability of wild and semi-cultivated senna across the Sahel region has made it one of the most accessible medicinal plants in African traditional pharmacy."
[2]
European/Western Herbalism
- Short-term laxative for occasional constipation
- Bowel preparation before diagnostic procedures
- Component of compound laxative formulations (often with carminatives to reduce griping)
- Traditional 'spring cleansing' purgative (historical, now discouraged)
- Pediatric constipation (senna pod infusion, milder than leaf)
"Senna entered European medicine via Arab traders and physicians during the Crusades and medieval spice trade (12th-13th centuries). It quickly became one of the most important drugs in European pharmacy. The 16th century herbalist Leonhart Fuchs depicted senna in De Historia Stirpium (1542). By the 17th-18th centuries, senna was a standard purgative in all European pharmacopeias. The British Pharmacopoeia, European Pharmacopoeia, and United States Pharmacopeia all include senna monographs to this day. In modern Western herbal practice, senna is used strictly as a short-term laxative and is almost always combined with carminative herbs (fennel, ginger, peppermint) to reduce the tendency toward griping and cramping."
Modern Research
Pharmacokinetics of sennosides and mechanism of action
Comprehensive pharmacological investigation into the metabolism and mechanism of action of sennosides, establishing the prodrug concept for anthraquinone glycoside laxatives.
Findings: Sennosides are not absorbed from the small intestine. They pass intact to the colon, where bacterial beta-glucosidases (primarily from Bifidobacterium and other anaerobic species) cleave the glycosidic bonds, first producing sennidin (the dianthrone aglycone) and then rhein anthrone, the active metabolite. Rhein anthrone acts via two mechanisms: (1) stimulation of peristalsis by acting on the submucosal (Meissner's) and myenteric (Auerbach's) plexuses, mediated in part through prostaglandin E2 and 5-HT release, and (2) alteration of colonic fluid transport by inhibiting Na+/K+-ATPase, leading to reduced water absorption and increased fluid secretion into the lumen. Only a small fraction of rhein is absorbed systemically and is excreted in urine (brown discoloration of urine is possible). Onset of action: 6-12 hours after oral administration.
Limitations: Much of the mechanistic work derives from in vitro and animal models. The relative contribution of the prokinetic versus prosecretory mechanisms in humans is not fully quantified. Individual variation in colonic microbiota composition may affect sennoside metabolism and clinical response.
Senna for bowel preparation before colonoscopy
Randomized endoscopist-blinded trial comparing senna (Sennae fructus extract) plus polyethylene glycol (PEG) solution versus standard high-volume PEG alone for bowel cleansing before colonoscopy.
Findings: Senna plus reduced-volume PEG (2 liters) provided equivalent or superior bowel cleanliness compared to standard full-volume PEG (4 liters) alone. Patient acceptability and compliance were significantly higher in the senna-PEG group due to lower volume of solution required. The combined regimen reduced the total volume of PEG by 50% while maintaining bowel preparation quality. No significant differences in adverse effects between groups.
Limitations: Single-center study. Specific senna preparation and dose may not be generalizable to all senna products. Endoscopist assessment of bowel preparation quality, while blinded, has inherent subjectivity.
[7]
Systematic review of stimulant laxatives for chronic constipation
Systematic review assessing the efficacy of stimulant laxatives (including senna) for chronic idiopathic constipation in adults.
Findings: Senna was found to be effective in increasing stool frequency and improving stool consistency compared to placebo. The review noted that despite senna's widespread use and long history, there are relatively few high-quality RCTs compared to newer laxative agents (e.g., lubiprostone, linaclotide). Available evidence supports efficacy for short-term relief of constipation. The review highlighted the lack of long-term safety data from controlled trials, noting that most long-term safety concerns are based on case reports and observational data rather than RCTs.
Limitations: Limited number of high-quality randomized trials specific to senna. Heterogeneity in preparations, doses, and outcome measures across studies. Most evidence supports short-term use; long-term RCT data is lacking.
[8]
Melanosis coli and long-term anthraquinone use
Investigation of melanosis coli (pseudomelanosis coli), a brownish-black pigmentation of the colonic mucosa associated with chronic anthraquinone laxative use.
Findings: Chronic use of anthraquinone laxatives (including senna) for periods typically exceeding 4-12 months leads to melanosis coli in a majority of users. The pigmentation results from lipofuscin deposition in macrophages in the lamina propria, caused by anthraquinone-induced apoptosis of colonic epithelial cells. Melanosis coli is considered a benign, reversible condition -- pigmentation typically resolves within 6-12 months of discontinuing anthraquinone laxatives. Earlier concerns that melanosis coli was a premalignant condition or was associated with increased colorectal cancer risk have not been substantiated by well-designed studies. However, melanosis coli serves as a clinical marker of chronic stimulant laxative use and should prompt evaluation of the patient's laxative habits.
Limitations: Most data comes from observational and case-control studies. Confounding factors (chronic constipation itself may be associated with colorectal pathology) complicate interpretation. Long-term prospective studies specifically addressing cancer risk with senna use are lacking.
Senna use in pregnancy: safety data
Analysis of pregnancy safety data for senna, including data from the Norwegian Mother and Child Cohort Study and other surveillance data.
Findings: The Norwegian Mother and Child Cohort Study (a large population-based prospective cohort) found no statistically significant association between senna use during pregnancy and increased risk of major congenital malformations. Sennosides are large molecules with limited systemic absorption, and only trace amounts of rhein reach systemic circulation. Studies on excretion into breast milk found that small amounts of rhein metabolites can be detected in breast milk, but at quantities insufficient to produce a laxative effect in the nursing infant. No changes in stool consistency were observed in breastfed infants of mothers taking senna at normal therapeutic doses. The EMA assessment concluded that senna may be used during pregnancy and lactation when dietary measures are insufficient, but should be used at the lowest effective dose for the shortest duration.
Limitations: Observational design limits causal inference. Potential for unmeasured confounders. Relatively small numbers of exposed pregnancies in some analyses limit statistical power for detecting rare outcomes.
Senna for constipation in elderly hospitalized patients
Randomized controlled trial evaluating senna-fiber combination versus placebo for management of constipation in elderly hospitalized patients.
Findings: Senna-fiber combination significantly improved bowel frequency and stool consistency compared to placebo in elderly hospitalized patients. The combination was well-tolerated with no serious adverse events. Abdominal cramping was reported in a minority of senna patients but was generally mild and transient. The study supported senna as an effective intervention for constipation management in the elderly hospital setting.
Limitations: Single-center study. Hospitalized population may not be generalizable to community-dwelling elderly. Short study duration. Combined intervention (senna + fiber) makes it difficult to isolate the effect of senna alone.
[9]
Preparations & Dosage
Infusion (Tea)
Strength: 1-2 g dried leaf or 0.5-2 g pods per 150-250 mL water
Place 1-2 g of dried senna leaflets (approximately 1-2 teaspoons) or 0.5-2 g of senna pods in 150-250 mL of just-boiled water. Steep for 10-15 minutes, covered. Strain and drink. Adding a carminative herb such as fennel seed (0.5-1 g), ginger, or peppermint to the infusion reduces the tendency toward griping.
One cup (150-250 mL) taken at bedtime. Do not exceed 2 cups per day. Use the lowest dose that produces comfortable bowel movement.
Once daily at bedtime (onset of action 6-12 hours, producing bowel movement the following morning). Maximum twice daily if once-daily dose is insufficient.
SHORT-TERM USE ONLY. Maximum 1-2 weeks without medical supervision. If constipation persists beyond 1 week, investigate underlying cause. Chronic use can lead to tolerance, dependency, and electrolyte depletion.
Children 6-12 years: approximately one-third to one-half adult dose (consult practitioner). Children 2-6 years: senna pod infusion only, under medical supervision. Not recommended for children under 2 years.
Traditional method of preparation. Senna pods (fruit) produce a milder infusion with less griping than the leaf. Combining with carminatives (fennel, ginger, anise) is traditional and pharmacologically rational to reduce intestinal cramping. Cold infusion (steeping in room-temperature water for 10-12 hours) is sometimes recommended as it extracts sennosides while leaving behind more of the resinous, griping-inducing compounds, potentially reducing side effects. Taste is bitter; honey or lemon may be added for palatability.
Standardized Extract
Strength: Standardized to 15-30 mg sennosides (as sennoside B) per dose
Commercially prepared standardized senna leaf or pod extracts in tablet or capsule form. Products should be standardized to sennoside content (calculated as sennoside B).
Standardized preparations delivering 15-30 mg sennosides (calculated as sennoside B) per dose. Typical starting dose: 15 mg sennosides at bedtime. May increase to 30 mg if needed. Maximum daily dose: 30 mg sennosides. Common commercial products: Senokot (standardized senna concentrate), Ex-Lax (sennosides), and various generic senna tablets (typically 8.6 mg sennosides per tablet -- take 2 tablets at bedtime).
Once daily at bedtime. Effect expected within 6-12 hours.
SHORT-TERM USE ONLY. Maximum 1-2 weeks without medical supervision.
Children 6-12 years: 7.5-15 mg sennosides at bedtime. Children 2-6 years: 3.75-7.5 mg sennosides, under medical supervision only. Follow product-specific dosing for pediatric formulations.
The most commonly used form of senna worldwide. Standardization ensures consistent dosing of active sennosides. OTC senna products (e.g., Senokot, Ex-Lax Senna) are among the most widely sold laxatives globally. Tablets provide precise dosing compared to infusion. Products standardized to sennoside content are preferred over crude unstandardized preparations for predictable effect. The WHO Essential Medicines List includes senna tablets standardized to sennoside content.
Syrup
Strength: Product-specific; typically standardized to sennoside content per mL
Commercially prepared senna syrup (liquid concentrate). Typically standardized to a defined sennoside content per mL or per dose.
Follow product-specific dosing. Typically 10-15 mL at bedtime (delivering approximately 15-30 mg sennosides depending on product concentration).
Once daily at bedtime
SHORT-TERM USE ONLY. Maximum 1-2 weeks.
Children 6-12 years: 5-10 mL. Children 2-6 years: 2.5-5 mL, under medical supervision. Senokot Children's Syrup is a commonly available pediatric formulation. Follow manufacturer's recommendations.
Liquid form is particularly useful for pediatric dosing (allows precise volume measurement) and for patients who have difficulty swallowing tablets. Also used in hospital and palliative care settings where liquid dosing is preferred. Senna syrup has a characteristically bitter taste; commercial products are usually flavored. Must be distinguished from senna tea/infusion -- syrup is a concentrated, standardized pharmaceutical preparation.
[4]
Tincture
Strength: Tincture: 1:5 in 25-45% ethanol. Liquid extract: 1:1 in 25% ethanol.
Macerate dried senna leaf in 25-45% ethanol at a ratio of 1:5 for 2-4 weeks. Press and filter. Alternatively, use commercially prepared senna liquid extract (1:1 in 25% ethanol).
Tincture (1:5): 2-4 mL at bedtime. Liquid extract (1:1): 0.5-2 mL at bedtime.
Once daily at bedtime
SHORT-TERM USE ONLY. Maximum 1-2 weeks.
Not recommended for children. Use standardized pediatric preparations (syrup or tablets) instead.
Less commonly used than tablets or tea in modern practice. Liquid extract allows for flexible dosing. Alcohol-based preparations are not suitable for patients who avoid alcohol. In clinical practice, standardized tablets or syrup are preferred for their predictable sennoside dosing.
[12]
combination-products
Strength: Product-specific
Senna is commonly combined with other agents to improve efficacy, reduce side effects, or address specific clinical scenarios. Common combinations include: (1) Senna + docusate sodium (stool softener) -- a widely used combination in palliative care and opioid-induced constipation. (2) Senna + psyllium or other bulk-forming fiber -- combines stimulant and bulk-forming mechanisms. (3) Senna + carminatives (fennel, ginger, peppermint) -- traditional combination to reduce griping.
Follow product-specific dosing. Senna-docusate combination: typically 8.6 mg sennosides + 50 mg docusate per tablet, 1-2 tablets at bedtime.
Typically once daily at bedtime
SHORT-TERM USE ONLY for senna component. Maximum 1-2 weeks unless under medical supervision.
Product-specific. Consult pharmacist or practitioner.
Senna + docusate sodium (e.g., Senokot-S, Peri-Colace) is one of the most commonly prescribed laxative combinations in hospital and palliative care settings. The docusate component softens stool while senna stimulates peristalsis, addressing both consistency and motility aspects of constipation. The addition of carminatives (fennel, ginger, peppermint) to senna in traditional herbal practice is well-justified pharmacologically: carminatives relax intestinal smooth muscle, counteracting the griping/cramping tendency of senna's stimulant action.
Safety & Interactions
Class 2b
Not to be used during lactation (AHPA Botanical Safety Handbook)
Contraindications
Stimulant laxatives are absolutely contraindicated in intestinal obstruction, whether mechanical or paralytic. Stimulating peristalsis against an obstruction can lead to bowel perforation, a life-threatening surgical emergency. Abdominal pain of unknown origin must be evaluated before administering senna to rule out obstruction or other surgical conditions.
Senna is contraindicated in active inflammatory bowel disease. The stimulant and irritant action of anthraquinone laxatives on already inflamed colonic mucosa can exacerbate inflammation, increase pain, and potentially trigger or worsen flares. The fluid and electrolyte losses from stimulant laxative use further complicate IBD management.
All stimulant laxatives are contraindicated in appendicitis. Stimulating colonic motility in the setting of appendiceal inflammation can precipitate perforation.
Undiagnosed abdominal pain must be evaluated before administering any stimulant laxative. Senna could mask symptoms of serious conditions (obstruction, appendicitis, volvulus) or worsen them. This is a standard contraindication for all stimulant laxatives.
Senna promotes fluid and electrolyte loss into the colonic lumen. In patients who are already dehydrated or who have existing electrolyte disturbances (especially hypokalemia), senna can dangerously worsen these imbalances. Hypokalemia from chronic senna abuse can potentiate cardiac arrhythmias and interact dangerously with cardiac glycosides and antiarrhythmic agents.
Stimulant laxatives are contraindicated in children under 2 years. The immature colonic mucosa and the risk of severe fluid and electrolyte disturbances make senna inappropriate for this age group.
Drug Interactions
| Drug / Class | Severity | Mechanism |
|---|---|---|
| Digoxin and other cardiac glycosides (Cardiac glycosides) | major | Chronic senna use can cause potassium depletion (hypokalemia). Hypokalemia significantly increases sensitivity to cardiac glycosides, potentiating their cardiotoxic effects (arrhythmias, heart block, cardiac arrest). This is a pharmacodynamic interaction mediated by electrolyte depletion, not a direct pharmacokinetic interaction. |
| Thiazide and loop diuretics (hydrochlorothiazide, furosemide) (Diuretics) | moderate | Additive potassium depletion. Both stimulant laxatives and potassium-wasting diuretics promote potassium loss. Concurrent use increases the risk of hypokalemia, which can lead to muscle weakness, cardiac arrhythmias, and potentiation of digoxin toxicity if digoxin is also co-prescribed. |
| Corticosteroids (prednisone, dexamethasone) (Corticosteroids) | moderate | Corticosteroids promote potassium excretion. Combined with potassium-depleting effects of chronic senna use, additive hypokalemia can occur. |
| Antiarrhythmic agents (quinidine, amiodarone, sotalol) (Antiarrhythmic agents) | moderate | Hypokalemia from chronic senna use can alter cardiac conduction and increase the risk of arrhythmias, particularly torsades de pointes with QT-prolonging antiarrhythmic agents. Senna-induced potassium depletion can reduce the efficacy and increase the toxicity of antiarrhythmic drugs. |
| Oral medications (general -- absorption consideration) (Various) | minor | Stimulant laxatives accelerate colonic transit, which could theoretically reduce the absorption of drugs primarily absorbed in the colon or drugs with extended-release colonic delivery mechanisms. Senna does not affect small intestinal transit or absorption. |
Pregnancy & Lactation
Pregnancy
caution
Lactation
likely safe
Pregnancy: Senna is classified as FDA Pregnancy Category C (animal reproduction studies have not been conducted, or have shown an adverse effect, and there are no adequate well-controlled studies in humans). The Norwegian Mother and Child Cohort Study found no increased risk of congenital malformations with senna use in pregnancy. Sennosides are large molecules that are poorly absorbed systemically; the active metabolite rhein reaches systemic circulation only in trace amounts. However, theoretical concerns include potential stimulation of uterine smooth muscle at very high doses (not demonstrated clinically at standard laxative doses). Senna may be used for constipation in pregnancy when dietary and lifestyle measures (fiber, fluids, exercise) and bulk-forming laxatives (psyllium) are insufficient, under medical supervision, at the lowest effective dose for the shortest duration. Avoid in the first trimester if possible. Lactation: Small amounts of rhein metabolites are excreted in breast milk. At normal therapeutic doses, no laxative effect has been observed in breastfed infants in published studies. Classified as compatible with breast-feeding by most authorities, though use at the lowest effective dose is recommended.
Adverse Effects
References
Monograph Sources
- [1] German Commission E (Bundesinstitut fur Arzneimittel und Medizinprodukte). Commission E Monograph: Sennae folium (Senna Leaf) and Sennae fructus (Senna Pod) -- Positive. Bundesanzeiger (Federal Gazette) (1998)
- [2] World Health Organization. WHO Monographs on Selected Medicinal Plants, Volume 1: Folium Sennae and Fructus Sennae. World Health Organization, Geneva (1999) : 241-258
- [3] European Scientific Cooperative on Phytotherapy (ESCOP). ESCOP Monographs: Sennae folium -- Senna Leaf; Sennae fructus -- Senna Fruit. ESCOP Monographs, 2nd edition. Thieme, Stuttgart (2003)
- [4] Committee on Herbal Medicinal Products (HMPC), European Medicines Agency. Community herbal monograph on Cassia senna L. and Cassia angustifolia Vahl, folium / Community herbal monograph on Cassia senna L. and Cassia angustifolia Vahl, fructus. European Medicines Agency (2007)
- [5] National Center for Complementary and Integrative Health (NCCIH). Senna. NCCIH, National Institutes of Health (2020)
Clinical Studies
- [6] Leng-Peschlow E. Sennoside figures and facts: basis for the use of standardized senna leaf preparations in clinical pharmacology. Pharmacology (2007) ; 44 : Suppl 1:1-22 . DOI: 10.1159/000139471 . PMID: 8234416
- [7] Radaelli F, Meucci G, Imperiali G, Spinzi G, Strocchi E, Terruzzi V, Minoli G. High-dose senna compared with conventional PEG-ES lavage as bowel preparation for elective colonoscopy: a prospective, randomized, investigator-blinded trial. Am J Gastroenterol (2005) ; 100 : 2674-2680 . DOI: 10.1111/j.1572-0241.2005.00335.x . PMID: 16393220
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- [9] Agra Y, Sacristan A, Gonzalez M, Ferrari M, Portugues A, Calvo MJ. Efficacy of senna versus lactulose in terminal cancer patients treated with opioids. J Pain Symptom Manage (1998) ; 15 : 1-7 . PMID: 9436335
- [10] Acs N, Banhidy F, Puho EH, Czeizel AE. Senna treatment in pregnant women and congenital abnormalities in their offspring -- a population-based case-control study. Reprod Toxicol (2009) ; 28 : 100-104 . DOI: 10.1016/j.reprotox.2009.02.005 . PMID: 19490990
- [11] Franz G. The senna drug and its chemistry. Pharmacology (1993) ; 47 : Suppl 1:159-166 . DOI: 10.1159/000139862 . PMID: 8234424
Traditional Texts
- [12] Bone K, Mills S. Principles and Practice of Phytotherapy: Modern Herbal Medicine (2nd edition). Churchill Livingstone/Elsevier (2013)
- [13] Blumenthal M, Busse WR, Goldberg A, Gruenwald J, Hall T, Riggins CW, Rister RS (eds). The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council, Austin, TX (1998)
Pharmacopeias & Reviews
- [14] European Directorate for the Quality of Medicines. European Pharmacopoeia: Sennae folium (Senna Leaf) and Sennae fructus (Senna Fruit). European Pharmacopoeia, Council of Europe, Strasbourg (2023) ; 11 : 1895-1897
- [15] United States Pharmacopeial Convention. USP Monograph: Sennosides Tablets, Senna Leaf, Senna Pods. United States Pharmacopeia - National Formulary (2023) ; USP 46-NF 41
Last updated: 2026-02-26 | Status: review