The Medline Senna Syrup, 8 oz bottle, is a natural vegetable laxative that promotes regularity. Helps relieve occasional constipation. Senna is an herb. The leaves and the fruit of the plant are used to make medicine. Senna is an FDA-approved nonprescription laxative. It is used to treat constipation and also to clear the bowel before diagnostic tests such as colonoscopy. 1 Count