Senna is a plant with bright yellow flowers. The flowers and leaves have been used as a laxative. Senna can be taken as a pill, powder, or extract. It can also be made into a tea.


15 to 30 milligrams twice daily

What Research Shows

Likely Effective

May Be Effective

  • Procedure preparation—has been used with standard treatment to help clear bowels B1-B9

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to take senna in small doses for a short time, but belly cramps, diarrhea, and skin blisters are possible. C3 Senna is a laxative and should not be taken for long periods of time as it may damage the liver. C1, C2


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse such as:

  • Senna is a laxative. It may make the medicines you take less effective.
  • People with heart problems should talk to their doctors before taking senna. It may interact with their medicines.


REFA Constipation

REFA1 Zhang CX. [Clinical observation on treatment of functional constipation with compound plantain-senna granules]. Zhongguo Zhong Xi Yi Jie He Za Zhi. 2009;29(12):1119-1122.

REFA2 Patel M, Schimpf MO, et al. The use of senna with docusate for postoperative constipation after pelvic reconstructive surgery: a randomized, double-blind, placebo-controlled trial. Am J Obstet Gynecol. 2010 May;202(5):479.e1-5.

REFA3 Tao LM, Xiong JP, et al. [A crossover control study of prophylactic treatment of chemotherapy-induced constipation by senna extract]. Zhongguo Zhong Xi Yi Jie He Za Zhi. 2012;32(1):47-49.

REFA4 Marciniak CM, Toledo S, et al. Lubiprostone vs Senna in postoperative orthopedic surgery patients with opioid-induced constipation: a double-blind, active-comparator trial. World J Gastroenterol. 2014 Nov 21;20(43):16323-33.

REFA5 Candy B, Jones L, et al. Laxatives for the management of constipation in people receiving palliative care. Cochrane Database Syst Rev. 2015 May 13;(5):CD003448.

REFA6 Santos-Jasso KA, Arredondo-García JL, et al. Effectiveness of senna vs polyethylene glycol as laxative therapy in children with constipation related to anorectal malformation. J Pediatr Surg. 2017 Jan;52(1):84-88.

REFA7 Alsalimy N, Madi L, et al. Efficacy and safety of laxatives for chronic constipation in long-term care settings: A systematic review. J Clin Pharm Ther. 2018 Oct;43(5):595-605.

REFB Procedure preparation

REFB1 Radaelli F, Meucci G, et al. High-dose senna compared with conventional PEG-ES lavage as bowel preparation for elective colonoscopy: a prospective, randomized, investigator-blinded trial. Am J Gastroenterol. 2005 Dec;100(12):2674-2680.

REFB2 De Salvo L, Borgonovo G, et al. The bowel cleansing for colonoscopy. A randomized trial comparing three methods. Ann Ital Chir. 2006 Mar-Apr;77(2):143-146; discussion 147. P

REFB3 Amato A, Radaelli F, et al. Half doses of PEG-ES and senna vs. high-dose senna for bowel cleansing before colonoscopy: a randomized, investigator-blinded trial. Am J Gastroenterol. 2010 Mar;105(3):675-681.

REFB4 Terry NA, Chen-Lim ML, et al. Polyethylene glycol powder solution versus senna for bowel preparation for colonoscopy in children. J Pediatr Gastroenterol Nutr. 2013 Feb;56(2):215-219. d

REFB5 Kierkus J, Horvath A, et al. High- versus low-volume polyethylene glycol plus laxative versus sennosides for colonoscopy preparation in children. J Pediatr Gastroenterol Nutr. 2013 Aug;57(2):230-235.

REFB6 Ergül B, Filik L, et al. Efficacy and safety of gum chewing in adjunct to high-dose senna for bowel cleansing before colonoscopy: a single-blind randomized controlled trial. Saudi J Gastroenterol. 2014;20(6):356-259.

REFB7 Tajima Y, Ishida H, et al. Comparison of the risk of surgical site infection and feasibility of surgery between sennoside versus polyethylene glycol as a mechanical bowel preparation of elective colon cancer surgery: a randomized controlled trial. Surg Today. 2016;46(6):735-740.

REFB8 Restellini S, Kherad O, et al. Systematic review and meta-analysis of colon cleansing preparations in patients with inflammatory bowel disease. World J Gastroenterol. 2017 Aug 28;23(32):5994-6002.

REFB9 Kamei M, Shibuya T, et al. Efficacy and Acceptability od 1 Liter of Polyethylene Glycol with Ascorbic Acid vs. 2 Liters of Polyethylene Glycol Plus Mosapride and Sennoside for Colonoscopy Preparation. Med Sci Monit. 2018;24:523-530.

REFC Safety

REFC1 Seybold U, Landauer N, et al. Senna-induced hepatitis in a poor metabolizer. Ann Intern Med. 2004 Oct 19;141(8):650-651.

REFC2 Vanderperren B, Rizzo M, et al. Acute liver failure with renal impairment related to the abuse of senna anthraquinone glycosides. Ann Pharmacother. 2005 Jul-Aug;39(7-8):1353-1357.

REFC3 Vilanova-Sanchez A, Gasior AC, et al. Are Senna based laxatives safe when used as long term treatment for constipation in children? J Pediatr Surg. 2018 Apr;53(4):722-727.

Revision Information

  • Reviewer: EBSCO NAT Review Board Eric Hurwitz, DC
  • Review Date: 07/2019
  • Update Date: 03/30/2020