Cassia angustifo/ia (senna), a native plant of Yemen, Somalia and Arabia and now cultivated in other parts of the world, has a variety of medicinal uses in Unani as well as other traditional systems of medicine. The plant is mainly valued for its cathartic properties and is specially useful in habitual constipation. The laxative principles sennoside A and sennoside B, isolated from leaves and pods of senna, constitute important ingredients in purgative medicines. The plant has been investigated for its various chemical constituents and pharmacological properties. Being a hardy species, it can be grown even in saline and rainfed conditions. Cultivation of senna does not require much expense on irrigation, manuring, pesticides, protection and other pre-and postharvesting care. This makes the plant an ideal crop for arid regions where water provision, wasteland development, desertification control, sand dune stabilization are the major challenges. The distribution, medicinal applications, chemical and pharmacological studies and various aspects of senna cultivation are reviewed in this paper.