1. Senna tea is made from the leaves of the senna plant. The active ingredients in senna are called glycosides and sennosides, which act as stimulants in the colon to increase peristalsis, or intestinal muscle contraction. In addition, these active ingredients allow the intestines to retain more fluid and have the effect of softening intestinal contents and stimulating stool emptying. As waste moves faster through the intestines, symptoms such as gas, bloating, cramping, and diarrhea can be induced. These are common side effects of senna tea and most other laxatives.

2. Senna is an herb commonly used to treat constipation. In fact, the U.S. Food and Drug Administration has approved senna for use as an over-the-counter laxative. In addition to being found in tea drinks and supplements, this herb is also an ingredient in many detoxifying teas. Because senna has a stimulating effect on defecation, tea containing this herb may cause gastrointestinal side effects, which may even be dangerous if used in high doses over a long period of time or in patients with certain medical conditions.