Conclusions 1. Atropine and morphine effectively block angiotensin and nicotine-induced spasm on the isolated guinea pig ileum. 2. Mecamylamine, pempidine, pentolinium and hexamethonium blocked nicotine-induced spasms; however, only mecamylamine and pempidine blocked angiotensin spasms, but very high concentrations were required. 3. It is proposed that angiotensin acts on the post-ganglionic cholinergic mechanism of the ileum and that its site of action is probably peripheral to the ganglion.