Botanical names: Cassia senna, Cassia
© Steven Foster
Parts used and where grown
The senna shrub grows in India, Pakistan, and China. The leaves and pods are used
Senna has been used in
connection with the following conditions (refer to the individual
health concern for complete information):
Bowel Surgery (preparation for)
Historical or traditional use (may
or may not be supported by scientific studies)
People in northern Africa and southwestern Asia have used senna as a laxative for
centuries. It was considered a “cleansing” herb because of its cathartic effect.
In addition, the leaves were sometimes made into a paste and applied to various skin diseases.
Ringworm and acne were both treated in this
Senna contains hydroxyanthracene glycosides known as sennosides. These glycosides stimulate
colon activity and thus have a laxative effect. Also, these glycosides increase fluid
secretion by the colon, with the effect of softening the stool and increasing its
bulk.1 Double-blind trials have confirmed the benefit of senna in treating constipation.2 3 Constipation
induced by drugs such as the anti-diarrhea
medicine loperamide (Imodium®) has also
been shown to be improved by senna in a clinical trial.4
A double-blind trial showed that senna was more effective as a preparatory agent for bowel
surgery than the commonly used polyethylene glycol (PEG).5 Patients scheduled to
undergo bowel surgery received either 120 mg of senna in a glass of water or 118 mg of PEG in
about 2–3 quarts of water the night before surgery. Surgeons rated the efficacy of senna
at clearing the bowels at 70%, compared to 58% efficacy for PEG. Supplementation with senna
for this purpose should always be supervised by the surgeon.
How much is usually taken?
People using over-the-counter senna products should carefully follow label instructions. An
extract in capsules or tablets providing 20–60 mg of sennosides per day is sometimes
recommended.6 This can be continued for a maximum of ten days. Use beyond ten days
is strongly discouraged. If constipation is not alleviated within ten days, people should seek
the help of a healthcare professional.
Are there any side effects or interactions?
Some people may develop a dependency on senna for normal bowel movements. Therefore, senna
must not be used for more than ten consecutive days. Chronic senna use can also cause loss of
fluids, low potassium levels and diarrhea, all of which can lead to dehydration and
potentially negative effects on the heart and muscles. The safety of senna during pregnancy and breast-feeding is controversial. Most
guidelines suggest avoiding senna during the first trimester of pregnancy.7
8 It is best to consult a physician. Senna is not recommended for children under the age
of ten years. People with Crohn’s
disease, ulcerative colitis, appendicitis,
intestinal obstructions, and abdominal pain should not supplement with senna.9
There is one case report of a woman who developed liver failure after ingesting a large
amount of senna (1 liter of a tea containing 70 grams of dried herb) daily for more than three
years.10 Senna was suspected, though not proven, to be the cause of the liver
Are there any drug
Certain medicines may interact with senna. Refer to drug interactions for a list of those medicines.
1. Leng-Peschlow E. Dual effect of orally administered sennosides on
large intestinal transit and fluid absorption in the rat. J Pharm Pharmacol
2. Passmore AP, Davies KW, Flanagan PG, et al. A comparison of Agiolax
and Lactulose in elderly patients with chronic constipation. Pharmacol 1993;47(suppl
3. Kinnunen O, Winblad I, Koistinen P, Salokannel J. Safety and efficacy
of a bulk laxative containing senna versus lactulose in the treatment of chronic constipation
in geriatric patients. Pharmacol 1993;47(suppl 1):253–5.
4. Ewe K, Ueberschaer B, Press AG. Influence of senna, fibre, and
fibre+senna on colonic transit in loperamide-induced constipation. Pharmacol
5. Valverde A, Hay JM, Fingerhut A, et al. Senna vs polyethylene glycol
for mechanical preparation the evening before elective colonic or rectal resection: a
multicenter controlled trial. French Association for Surgical Research. Arch Surg
6. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal
Medicines. Montvale, NJ: Medical Economics, 1998, 722–4.
7. Mengs U. Reproductive toxicological investigations with sennosides.
8. Faber P, Strenge-Hesse A. Relevance of rhein excretion into breast
milk. Pharmacol 1988;36(suppl 1):212–20.
9. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete
Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative
Medicine Communications, 1998, 204–8.
10. Vanderperren B, Rizzo M, Angenot L, et al. Acute liver failure with
renal impairment related to the abuse of senna anthraquinone glycosides. Ann