Antiulcerative effect : Oxymatrine inhibited the formation of ulcers caused by pylorus ligation or by indomethacin administration. This effect was considered to be related to the inhibition of acid secretion. When administered intraduodenally in rats, oxymatrine reduced acid secretion and inhibited gastric motility induced by experimental stress. Thus, the protective effect by oxymatrine on stress ulcer appears to be due to a decrease in acid secretion and inhibition of gastric motility. On the other hand, matrine showed only a weak inhibition of gastric acid secretion, but was fairly effective in preventing stress ulcer after intravenous administration.