Senna leaves are harvested from Cassia senna plants, and they’re used to make herbal laxatives. The U.S. Food and Drug Administration has approved senna for use in over-the-counter medications. It’s generally safe to use, but it does have side effects. Speak to your doctor before taking senna leaf products.
Senna laxatives and senna leaf tea are effective for treating constipation, a condition in which you have infrequent bowel movements or where fecal material is difficult to pass. Senna works as a laxative because it contains natural chemicals called sennosides that irritate your intestinal wall and stimulate bowel movements. It also reduces the time it takes for the foods you eat to pass through your digestive system. Senna leaves might also help to reduce hemorrhoids, which are swollen veins near your anus. They might also provide relief for irritable bowel disease.
Senna is safe for short-term use for anyone over the age of 2, although it isn’t recommended during pregnancy. According to Medline Plus, women who are breast-feeding can take senna because only a small amount of the sennosides pass into breast milk and appear to be harmless. Long-term use of senna might result in laxative dependency and liver damage.
Senna might cause dehydration, diarrhea or loose stools, so you might need to drink more water when you take senna. It may increase abdominal pain in people with conditions such as Crohn’s disease, ulcerative colitis and appendicitis. It can also cause electrolyte imbalances. Electrolytes include sodium and potassium, which are necessary to balance your body’s fluid levels and maintain normal nerve transmission.
Senna might interact or interfere with some medications, herbs and supplements. It may interact with heart medications because it lowers your potassium levels. Potassium is needed for normal heart beats. The loss of potassium might also interact with diuretics, which are drugs that remove excess water from your body. Senna won’t interact with any of the foods you eat, but it may increase the laxative effect of herbal preparations that contain horsetail, licorice or other stimulant laxatives, such as aloe, manna, rhubarb and yellow dock.
Sheri Kay has a master's degree in human nutrition. She's the co-author of two books and has been a nutrition and fitness writer since 2004.