Pepto-Bismol liquid (primary active constituent, bismuth subsalicy-late) protected the gastric mucosa of rats against the formation of hemorrhagic lesions or erosions in response to cold + restraint stress, to a combination of aspirin and cold + restraint stress, and to ethyl alcohol. The protective effect of Pepto-Bismol in these studies was clearly demonstrated. Although the mechanism of action of Pepto-Bismol was not delineated, there was a suggestion that the degree of coating of the gastric mucosa was related to protection.