Herbs for Constipation: Senna, Cascara, Psyllium and Cautions
What EU, US and UK health sources say about senna, cascara and psyllium (ispaghula) for constipation, why stimulant herbs are for short use only, and who should not take them.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
Start with the basics
The NHS says constipation can often be treated with diet and lifestyle changes, and that most adults should try those before laxatives. [1][5] Common causes include too little fiber, too few fluids and some medicines. [1] See constipation: what helps and when to get checked and fiber, fluids and meal patterns. If you think a medicine you take causes constipation, ask the prescriber; do not stop it on your own. [6]The plants, by name and part
| Product | Plant and part | What the sources say | Evidence label |
|---|---|---|---|
| Senna | Senna alexandrina Mill., leaf [2][7] | EU committee: short-term use for occasional constipation, "well-established use," based on laboratory work, clinical experience and studies mostly in older people with long-term constipation. [2] | Regulator-accepted for short-term use |
| Cascara | Rhamnus purshiana DC. bark [3] (GBIF lists the accepted name as Frangula purshiana subsp. purshiana) [7] | EU committee: short-term use for occasional constipation. It also says there are no studies of cascara alone, so the conclusion rests on clinical experience and studies of other anthraquinone-containing substances. [3] | Regulator-accepted, but no direct trials |
| Psyllium (ispaghula) | Plantago ovata Forssk., seed [8][7] | EU committee: habitual constipation; ispaghula husk has been studied in over 900 patients as a mild laxative. [8] The NHS suggests a bulk-forming laxative first when buying without a prescription. [5] | Regulator-accepted; NHS suggests trying first when buying without a prescription |
How the types work: stimulant laxatives such as senna trigger the bowel muscles and work in about 6 to 12 hours, while bulk-forming types add fiber and are slower. [5]
Traditional use
Not described in the sources we read for this page. For other plants sometimes called natural laxatives, see the profiles for aloe and senna.Quality
How to check a product is covered in quality testing and how herb-drug interactions happen.Frequently asked questions
Is senna a natural laxative I can use every day?
No. The EU committee says not longer than one week, and long-term use may lead to the bowels not working properly and dependence. [2]
Is cascara proven?
The EU committee accepts it for short-term occasional constipation, but says there are no studies of cascara alone. [3]
Is psyllium safer than senna?
Sources describe different risks. The NHS suggests a bulk-forming laxative first, but the EU warns about hard stool without enough liquid and allergic reactions. [5][8]
When should I see a clinician about constipation?
If it is not improving, keeps returning, or comes with blood, weight loss, tummy pain or a sudden change in bowel habits. [1]
Can laxative herbs help with weight loss?
Proper evidence not found in the sources we read for this page. See herbs for weight loss: claims checked.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Warning signs first, and a short-use rule
Constipation that comes with blood in the stool, weight loss without trying, tummy pain, or a sudden change in your usual bowel habits should be checked by a clinician before any herbal laxative. [1] Constipation that keeps coming back, or regular bloating, also needs a visit. [1] Herbal stimulant laxatives are meant for the short term. The EU herbal committee says senna leaf and cascara should not be taken for longer than one week, [2][3] MedlinePlus says not more than one week without talking to a doctor, [4] and the NHS says non-prescription laxatives should not be used for longer than 7 days. [5] Long-term use may cause low potassium (muscle weakness, tiredness, heart rhythm problems) and dehydration. [5]
Safety by group
- Pregnancy and breastfeeding: the EU summaries say senna and cascara medicines must not be taken during pregnancy or breastfeeding or by children under 12. [2][3] The NHS says to check with a pharmacist or doctor first. [5]
- Children: the NHS says babies and children can have laxatives if a GP recommends them. [5] The EU limits above apply to herbal senna and cascara. [2]
- Older adults: MedlinePlus says older adults should not usually use senna over a long period. [4]
- Medicines: EU committee: people taking certain medicines should consult a doctor before senna. [2] MedlinePlus: some senna products may affect how other medicines work. [4] The NHS says to check first if you take opioid painkillers or have a heart condition. [5] See medicine interactions.
- Bowel conditions: the EU says senna and cascara must not be used with bowel blockage, appendicitis, Crohn's disease, ulcerative colitis, unexplained belly pain or severe dehydration. [2]
- Side effects and long-term use: allergic reactions, belly pain and diarrhea; with long use, changes in the bowel lining, salt and water imbalance, protein or blood in the urine, and colored urine. [2] MedlinePlus says frequent or continued senna use may cause dependence on laxatives, and rectal bleeding means stop and call a doctor. [4]
- Psyllium: the EU committee advises plenty of liquid, warns of hard, dry stool if swallowed with too little liquid, and lists allergic reactions including anaphylaxis. [8] It should not be used with a sudden bowel change lasting more than two weeks, undiagnosed rectal bleeding, narrowing of the gut or trouble swallowing. [8]
- Liver, kidney, surgery: liver and kidney effects of these products are not described in the sources we read. Tell the surgical team about every laxative; MedlinePlus notes senna is also used to empty the bowel before procedures. [4]
References
- NHS (UK). Constipation. Page last reviewed 26 October 2023. Read 2026-10-23.
- EMA, HMPC. Senna leaf: summary for the public. Read 2026-10-23.
- EMA, HMPC. Cascara: summary for the public. Read 2026-10-23.
- MedlinePlus (U.S. National Library of Medicine). Senna. Read 2026-10-23.
- NHS (UK). Laxatives. Page last reviewed 30 April 2026. Read 2026-10-23.
- NIDDK, NIH. Treatment for Constipation. Last reviewed May 2018. Read 2026-10-23.
- GBIF Backbone Taxonomy, species match service (api.gbif.org/v1/species/match), queried for each scientific name used on this page. Read 2026-10-23.
- EMA, HMPC. Ispaghula seed: summary for the public. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.