Senna (Cassia senna, C. acutifolia, C. angustifolia, C. marilandica [Latin]), also known as cassia, has been used as a laxative since the ninth century. It contains anthraquinones that interact with bacteria in the digestive tract to cause intestinal contractions.
Senna is an active ingredient in many well-known commercial laxatives. You can buy a more natural, undiluted form of senna
at some health-food stores. Senna is available in supplements and liquid extract form. The usual dose is 50 to 100 milligrams in capsules or up to ½ teaspoon of liquid leaf extract each day; however, you can also purchase dried senna pods and brew your own senna tea. Three to six pods to one cup of water makes an excellent laxative, but this form of senna is very strong and tastes terrible. If you are up to trying it, you should definitely use it with something that promotes digestion, such as mint or ginger
You should not take senna for more than a week, or a dependency may develop. Also, some studies indicate that prolonged use of senna can cause toxicity and increase the risk of colon cancer. However, senna is no substitute for the anti-cancer and overall health benefits of high-fiber diet.
Senna is a proven spasmodic, and should never be used by people suffering from serious digestive disorders such as Crohn's disease.