Used primarily as a stimulant laxative to treat constipation. It works by increasing intestinal motility and promoting water retention in the colon, which helps soften stool and induce bowel movements. Commonly found in herbal remedies derived from senna plant extracts. Often used in over-the-counter constipation treatments and sometimes prior to medical procedures requiring bowel cleansing. Its effects typically occur within 6 to 12 hours after ingestion.