Senna (Senna alexandrina): Uses, Evidence and Safety

Safety first: senna is for short-term use only. The EU herbal committee (HMPC) says senna leaf medicines should not be taken for longer than one week, and that long-term laxative use may lead to the bowels not working properly and to dependence on laxatives. [1] The UK NHS says not to take senna for more than 7 days unless a doctor or pharmacist advises it. [2] Laxatives can also be misused. The NHS lists taking laxatives among purging behaviors in bulimia and warns of physical problems from overusing them. [3] If this is a concern for you or someone you know, see eating disorders, weight-loss supplements and laxative misuse and recognizing and getting help. In the US, call or text 988 in a crisis, and call 911 in an emergency.

What senna is

Senna leaf is the leaf of Senna alexandrina Mill., according to the EU herbal committee, which names Cassia senna L. and Cassia angustifolia Vahl in the same entry. [1] GBIF accepts Senna alexandrina Mill., family Fabaceae. [4] The EU has separate monographs for the leaf and the fruit (pod). [1] This page is mainly about the leaf. The NHS describes senna as a stimulant laxative. [2] For the tea, see senna and other laxative teas.

What research and official bodies say

Senna is unusual among herbs because it has a long-established medical role.

Forms

The EU committee says senna leaf preparations are standardized to a defined amount of anthraquinones (the active laxative compounds) and come as herbal tea or solid and liquid forms. [1] The NHS describes tablets and liquid. [2] A tea, tablet and extract are not interchangeable.

Safety

• Side effects: allergic reactions (itching, rash), belly pain, spasm and diarrhea; yellow or red-brown urine is harmless. [1][2] Systematic review authors list abdominal pain, cramping, bloating, diarrhea and nausea as the common effects of over-the-counter products. [6]
• Low potassium: the NHS lists low blood potassium (muscle weakness, tiredness, heart rhythm problems) as a serious effect that can follow frequent diarrhea after long use. [2] Purging in eating disorders can cause chronic low potassium and kidney damage. [7]
• Medicines: the EU monograph says people taking heart glycosides, antiarrhythmics, QT-prolonging medicines, diuretics, corticosteroids or licorice root should consult a doctor first. [8] The NHS names heart medicines, diuretics, steroids and anything made with licorice root. [2] See how interactions work and ask a pharmacist.
• Bowel conditions: the NHS says senna may not suit people with irritable bowel syndrome, diverticular disease, Crohn's disease or a blockage. [2] The EU monograph lists intestinal obstruction, appendicitis, inflammatory bowel disease, unexplained belly pain and severe dehydration as contraindications. [8]
• Pregnancy and breastfeeding: sources differ. The EU committee says senna must not be taken during pregnancy or breastfeeding, citing experimental data on a genotoxic risk of related compounds (anthranoids). [1][8] The NHS says most pregnant people can usually take it but should speak to a pharmacist or doctor, and that it can be taken while breastfeeding if the baby is 1 month or older. [2] Ask a clinician; see pregnancy and breastfeeding.
• Children: the EU committee and NHS both place the line at age 12; younger children only on a doctor's prescription in the UK. [1][2] See children and teens.
• Liver: LiverTox (NIH) says senna is generally well tolerated but can cause clinically apparent liver injury at high doses over longer than recommended periods. [9]
• Kidney: people with kidney disorders should be aware of possible electrolyte imbalance. [8]
• Daily use: the EU monograph says if laxatives are needed every day, the cause of the constipation should be investigated. [8]

Related pages

Herbs for constipation and bowel regularity, cascara sagrada and herb quality.