Senna leaf (Cassia angustifolia) is a potent, FDA-approved herbal stimulant laxative used for short-term relief of constipation, typically working within 6–12 hours by irritating the intestinal lining to induce bowel movements. It is used for colon cleansing before medical procedures and may assist with hemorrhoid management. It is available as tea, powder, and tablets, but should not be used long-term.