Cascara

BotanicalBest before bed

What is it

Cascara sagrada (Rhamnus purshiana, also Frangula purshiana) is a tree bark used as a stimulant laxative. It contains anthraquinone glycosides that act on the colon.

Evidence for 1 use

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

Short-term constipation relief

Good Evidence

Anthraquinone laxatives produce reliable bowel evacuation for short-term constipation. Long-term reliance is discouraged.

How it works

Cascara contains cascarosides A through D and related anthranoids. After ingestion, gut bacteria convert these glycosides to aglycones that stimulate colonic peristalsis and inhibit water reabsorption, producing a laxative effect that typically occurs 6 to 12 hours after dosing. This mechanism is similar to senna and rhubarb. Long-term use can lead to dependence, electrolyte imbalance, and possible structural changes to the colon.

Dosage

Traditional doses range from 20 to 30 mg of hydroxyanthracene derivatives per day. The FDA in 2002 removed cascara from the over-the-counter laxative monograph due to lack of submitted safety data, though it remains available as a dietary supplement.

When and how to take it

Take at bedtime so the laxative effect occurs the following morning. Use only short-term, not as a daily routine.

1 commercial form

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

Aged cascara bark extract

Available as capsules, tablets, or tinctures, often combined with milder herbal laxatives.

Aged for at least one year before use to reduce GI irritation from fresh bark.

Safety

Short-term use is generally safe. Long-term use (over 1 to 2 weeks) is discouraged due to risk of laxative dependence, electrolyte loss (especially potassium), and concerns about colonic damage.

Who should be cautious

Avoid in pregnancy, lactation, children, intestinal obstruction, inflammatory bowel disease, appendicitis, abdominal pain of unknown cause, and chronic kidney disease.

Interactions

Potassium loss from chronic cascara use can increase digoxin toxicity and amplify effects of other diuretics. May interfere with absorption of orally administered medications.

Frequently asked questions

How long can I take cascara?⌄

Limit to short-term use, ideally no more than one to two weeks. For chronic constipation, work with a clinician on safer approaches.

Is cascara safe?⌄

For short-term use, generally yes. Long-term use carries real risks including dependence and electrolyte imbalance.

References

Cascara on Wikidata — Wikidata link

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

Research on Cascara (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.