The present study was designed to clarify the effects of an ethanol extract of artichoke leaf on acute gastric mucosal injury in rats. Oral administration of artichoke leaf extract dose-dependently prevented absolute ethanol-induced (125-500 mg/kg) or restraint plus water immersion stress-induced gastric mucosal injury (1000-2000 mg/kg). The artichoke leaf extract contains 1% cynaropicrin and 0.8% chlorogenic acid as main components and 70% dextrin as a vehicle. Cynaropicrin at doses of 1/100 of artichoke leaf extract [ethanol-induced mucosal injury: 5 mg/kg, per os (p.o.); stress-induced mucosal injury: 20 mg/kg, p.o.] also prevented gastric mucosal injury in both animal models. However, dextrin and chlorogenic acid at doses contained in the leaf extract were ineffective in both models. When artichoke leaf extract was given orally to normal rats, it (500-2000 mg/kg, p.o.) dose-dependently increased gastric mucus content. In addition, it (125-500 mg/kg, p.o.) dose-dependently prevented the decrease in gastric mucus content by absolute ethanol. When the effects of artichoke leaf extract on basal gastric acid secretion in rats were evaluated, it (500-2000 mg/kg, p.o.) dose-dependently increased the volume of gastric juice in normal rats. However, it was ineffective in decreasing basal gastric acid secretion in normal rats. These results indicate that artichoke leaf extract is effective against acute gastritis and its beneficial effect is due to that of cynaropicrin. The gastric mucus-increasing action of artichoke leaf extract may be, at least in part, related to the anti-gastritic action of the extract.