Senna leaves are small, dark green, and oval-shaped. They have a pungent odor and a bitter taste. They are used as a laxative and for other medicinal purposes. Senna leaves are native to tropical regions of Asia and Africa but are now grown in many other parts of the world. The leaves are dried, ground, and used in herbal teas, ointments, and capsules. They have been used for centuries to treat digestive and gastrointestinal issues, as well as to reduce inflammation.