Sennoside A is a dianthrone glycoside with laxative and gastroprotective activities.^1,2 Ex vivo, sennoside A (30 mg/kg) increases the amplitude of distal colon contractions in circular and longitudinal muscle and decreases the amplitude of proximal colon contractions in circular muscle in mice.¹ Sennoside A (100 mg/kg, oral) increases the gastric emptying rate by 71.1% compared to control and increases the intestinal transport rate of a charcoal meal from 61.2 to 81.1% in mice.² It increases the concentration of prostaglandin E2 (PGE2) in AGS gastric cells in a dose-dependent manner in vitro. Intraduodenal administration of sennoside A (100 mg/kg) increases gastric juice pH and decreases gastric juice secretion volume and total acid output in pylorus-ligated rats. It also reduces lesion indices by 43.1 and 36% in HCl/ethanol-induced gastritis and indomethacin-induced gastric ulcer rat models, respectively, when administered at a dose of 100 mg/kg. Sennoside A is also a non-competitive inhibitor of bovine serum monoamine oxidase in vitro (IC50 = 17 µM).³ Formulations containing sennoside A have been used to treat constipation and to aid in evacuation of the bowel prior to surgery or invasive colonic or rectal examinations.