- The leaves or pods of the senna plant (Cassia senna) have been used by Arab physicians for their laxative properties since at least the ninth Century. Today, senna is a U.S. Food and Drug Administration (FDA)-approved nonprescription drug and an ingredient in several commercial laxatives.
- There are over 400 known species of Cassia. Both the leaves and the seedpods (fruit) have laxative activity, due to the presence of compounds called anthraquinones. These compounds found in senna are also found in other plants with laxative properties, including cascara (Cascara sagrada), rhubarb (Rheum spp.), and aloe (Aloe vera). Senna accelerates defecation, in contrast to softening the stools, as some laxatives do. When taken at much higher than recommended doses or when used for the long term (laxative abuse), adverse effects, such as low blood potassium, may occur.
- Some evidence supports the use of senna in adults for the treatment of chronic constipation or constipation induced by childbirth or drugs. In children, the available evidence suggests that mineral oil and lactulose may be safer and more effective than senna for treating chronic constipation. Some experts believe that senna is a more acceptable laxative than cascara or aloe for drug-induced constipation. Approximately 80% of terminal cancer patients who are taking opioids for pain relief require laxatives. Some evidence suggests that senna may be as effective and safe as lactulose for these patients.