Senna, the sennas, is a large genus of flowering plants in the legume family. This diverse genus is native throughout the tropics, with a small number of species in temperate regions.
 
Senna is the fruit (pod) or leaf of the plant Senna alexandrina. It is approved in the US as a laxative for short-term treatment of constipation.
Senna contains many chemicals called sennosides. Sennosides irritate the lining of the bowel, which causes a laxative effect.
 
Senna is an FDA-approved over-the-counter (OTC) laxative. It is used to treat constipation and also to clear the bowel before procedures such as colonoscopy. People also use senna for irritable bowel syndrome (IBS), hemorrhoids, weight loss, and many other conditions