Senna: benefits, dosage, contraindications

Mis à jour le 7 November 2025

Senna is a perennial herbaceous plant of the Fabaceae family, native to Yemen, Somalia and India. From the 9th century, Arab physicians used senna in medicine as a laxative. The leaves and the fruits (pods) are used therapeutically. Senna mainly contains sennosides A and B, high-molecular-weight dianthrone glycosides, representing about 2.5% of the active components. These sennosides are prodrugs that are not absorbed by the gastrointestinal tract. They are hydrolyzed by enteric bacteria into active rheinanthrone monoanthrones, which increase colonic motility. The laxative effect generally occurs between 6 to 10 hours after ingestion of senna, leading to bowel evacuation. Senna, in accordance with the European Pharmacopoeia monograph, must contain at least 2.5% hydroxyanthracene glycosides calculated as sennoside B, relative to the dried plant. Its use is indicated for short-term treatment of occasional constipation.

Other name(s)

Senna alexandrina, Cassia angustifolia

Scientific name(s)

Cassia angustifolia

Family or group:

Plants

Active ingredients:

Sennosides

Indications

Scoring methodology

EFSA approval.

Several randomized, double-blind, controlled clinical trials (> 2), including a significant number of patients (>100), with consistently positive conclusions for the indication.

Several randomized, double-blind, controlled clinical trials (> 2), including a significant number of patients (>100), with positive conclusions for the indication.

One or more randomized studies, or several cohorts or epidemiological studies, with positive conclusions for the indication.

Clinical studies exist but are uncontrolled, with conclusions that may be positive or conflicting.

No clinical studies to date that can demonstrate the indication.

Constipation
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Senna is approved by the FDA as an over-the-counter medication for the short-term treatment of constipation in adults and children aged 2 years and older. It is generally effective 6 to 10 hours after oral administration. Although senna is often compared to alternatives such as mineral oil, lactulose in children, and psyllium, research indicates that senna, combined with psyllium, is particularly effective at increasing stool moisture more than psyllium alone. In the context of opioid- or loperamide-induced constipation, senna is also as effective as lactulose, psyllium, and docusate (a stool softener). Research in specific populations, such as pediatric cancer patients on opioids, suggests that senna may be more effective than docusate, polyethylene glycol, and lactulose for preventing constipation. A small study in middle-aged adults with chronic idiopathic constipation showed that 500 mg of senna taken twice daily for 4 weeks was as effective as 500 mg of magnesium oxide taken three times daily. The EMA and ESCOP recommend short-term use of senna to treat occasional constipation. Senna is generally used at a dose of 15 mg of sennosides once daily. The maximum dose is 30 mg of sennosides per day.

Posologie

Oral: leaf, fruit

15 - 30 mg

standardized extract

Synergies

Blond psyllium

American Gastroenterological Association-American College of Gastroenterology Clinical Practice Guideline: Pharmacological Management of Chronic Idiopathic Constipation
Senna Versus Magnesium Oxide for the Treatment of Chronic Constipation: A Randomized, Placebo-Controlled Trial
E/S/C/O/P: 2nd Edition of the ESCOP Monographs
European Union herbal monograph on Senna alexandrina Mill. (Cassia senna L.; Cassia angustifolia Vahl) 1, leaf

Properties

Laxative

Senna is used as a stimulant laxative due to the sennosides in its leaves and fruits. It acts via a selective effect on the enteric nerve plexus of the intestinal smooth muscles, increasing colonic motility and accelerating transit. This laxative effect usually occurs 6 to 10 hours after ingestion. Proposed mechanisms also include modulation of prostaglandins and serotonin in the colon.

Usages associés

Constipation

Laxatives and the special role of senna
Influence of senna, fiber, and fiber + senna on colonic transit in loperamide-induced constipation

Safe dosage

Adults aged 18 years and older: 15 mg - 30 mg (standardized sennoside extract)

For the use of senna to treat occasional constipation, the recommended dosage for adults and children over 10 years is to take once daily, preferably in the evening, preparations equivalent to 15-30 mg of sennosides, calculated as sennoside B. Elderly people may follow the same dose as adults.

Children aged 10 to 18 years: 15 mg - 30 mg (standardized sennoside extract)

It is important to note that the use of senna is not recommended for children under 10 years of age.

Pregnant women: 15 mg - 30 mg (standardized sennoside extract)

For pregnant women, appropriate short-term oral use of senna is considered safe. However, long-term, frequent, or high-dose use may be potentially dangerous, being associated with serious adverse effects such as laxative dependence and liver toxicity.

Breastfeeding women: 15 mg - 30 mg (standardized sennoside extract)

During breastfeeding, appropriate short-term oral use of senna is also considered safe. Although small amounts of senna components pass into breast milk, it has been used during breastfeeding without apparent problems for infants. Senna does not cause changes in the frequency or consistency of infants' stools.

Interactions

Médicaments

Estrogens: moderate interaction

Some preliminary clinical data suggest that senna reduces the absorption of estradiol by reducing intestinal transit time.

Conseil scientifique