Senna, or cassia, is an herb that has been used as a laxative for over a thousand years. This herb is also known as India senna, tinnevelly senna, Cassia senna, Khartoum senna, and Alexandrian senna. Senna contains anthraquinone, which causes intestinal contractions by interacting with bacteria in the digestive track. The leaves and pods of the plant are used for people suffering from constipation.

Found in many commercial laxatives, senna is also found undiluted at health food stores. It is available as a liquid extract, dried pods, or capsules. The recommended dosage is one half teaspoon of liquid leaf extract or 50 to 100 mg capsules. Dried senna pods can be brewed into a tea, using three to six dried senna pods for each cup of water. As senna tastes very unpleasant, the tea should be mixed with another flavor.

When taken before bed, senna will produce a bowel movement in the morning, 6 to 12 hours later. Senna should be kept kept in a dark dry area, protected from both light and moisture. Anyone taking senna should follow the directions on the package carefully.

Senna should not be taken for more than a week straight, or a senna dependency can develop. There are many side effects that may occur from using senna, including toxicity and increased risk of colon cancer. Diarrhea can occur from senna, as can pigmentation of the colon, laxative dependency, and enlargement of the ends of the toes and fingers. Senna may also discolor the urine.

People suffering from Crohn's disease or other serious digestive diseases should not use senna. It should not be used by people with diverticular disease, colitis, congestive heart failure, gastrointestinal cancer, liver disease, kidney disease, or recent colon surgery.

Always inform your physician about which herbal supplements you are taking, as they may interact with other medications. A trained herbalist may be able to offer additional information about herbal supplements.