Hydrastinine is a synthetic alkaloid prepared by various processes from either hydrastine, berberine, or narcotine. It exerts a strong stimulating action on the uterus of all species studied, including human. Hydrastinine and the closely related alkaloid cotarnine have been employed as hemostatics, particularly in abnormal uterine conditions. In the non-pregnant animal, hydrastinine in doses of 10 mg. depressed both tonus and activity, even after the section of the hypogastric. In the pregnant cat, it caused the uterus to contract. A stimulant action was also noted in the non-pregnant animal if nicotine were administered prior to hydrastinine. The rabbit uterus in situ was strongly contracted. Laidlaw believed that hydrastinine acted on the uterus both directly on the smooth muscle and also through its sympathetic innervation. Repeated administration of large doses for a period of time resulted in greatly increased amplitude of contractions which persisted after removal of the drug. The drug was patented by Bayer as a haemostatic drug during the 1910s.