Abstract:On experimental gastric ulcer models induced by 0. 6mollL HCl,ethyl alcohol or ligation of,he pylorus, thepreventive effects of unprepared oyster shell,calcined oyster shell 1 (900℃, lh) ,calcined oyster shell 2 (350℃, sh)were compared in Wistar rats. Results showed that antagonistic effects of calcined oyster shell I to the drug patho-genesis of peptic ulcer and the incidence of peptic ulcer after ligation of the pylorus were markedly greater.