Tiopinac is a tricyclic compound with anti-inflammatory and analgesic effects in animals, ability to inhibit prostaglandin synthesis, and modest antiplatelet aggregation properties in humans. The manufacturer withdrew tiopinac from investigation because of toxicity at higher doses. Tiopinac did not have significant cardiovascular or CNS activity. Lack of anorexia and emesis in dogs with up to 30 mg/kg p.o. and mild oral activity in producing gastric erosion in acute and subacute studies in rats suggests that tiopinac may have relatively little gastrointestinal irritating activity.