Alexandrian senna

BotanicalBest before bed

What is it

Alexandrian senna (Senna alexandrina, formerly Cassia angustifolia) is a flowering plant whose leaves and pods contain sennosides, plant compounds with strong stimulant laxative activity.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Short-term constipation relief

Strong Evidence

Senna has strong, well-established evidence as a stimulant laxative for short-term constipation, including bowel prep and opioid-induced constipation.

How it works

Sennosides are inactive prodrugs that are converted by colon bacteria to rhein anthrone, which stimulates intestinal motility and water secretion in the colon. The result is a bowel movement, typically within 6-12 hours of oral dosing. Senna is an FDA-recognized over-the-counter stimulant laxative.

Dosage

Standard adult laxative dose is 15-30 mg of sennosides at bedtime (often 1-2 tablets of standardized senna). Higher doses are not generally more effective and increase side effects.

When and how to take it

Taken at bedtime for next-morning relief. Not for daily long-term use.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Standardized sennoside tablets

Most consistent dosing.

Sennosides activated by colon bacteria; effect develops over hours.

Senna leaf or pod tea

Traditional and over-the-counter.

Variable potency.

Safety

Effective for short-term constipation relief. Chronic use can cause electrolyte abnormalities (potassium loss), dependency, and a reversible pigment change in the colon (melanosis coli). Not recommended for daily long-term use without medical supervision.

Who should be cautious

Avoid in suspected bowel obstruction, severe abdominal pain, IBD flares, and dehydration. Not recommended for children under 12 without medical advice. Pregnancy and breastfeeding: short-term use considered acceptable, but discuss with a clinician.

Interactions

Potassium loss can affect cardiac glycosides (digoxin), diuretics, and corticosteroids. May reduce absorption of other oral medications taken at the same time.

Food sources

Senna leaf tea (variable sennoside content)

Amount
variable
%DV
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Frequently asked questions

Can I take senna every day?⌄

Not for prolonged periods without medical supervision. Daily long-term use can cause dependency and electrolyte problems. Address the underlying constipation cause and consider fiber and hydration first.

How quickly does senna work?⌄

Typically within 6-12 hours, so most people take it at bedtime for a morning bowel movement.

References

Alexandrian senna on Wikidata — Wikidata link

Alexandrian senna on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Alexandrian senna (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.