Objectives : The objective of this study was to examine the effects of P. oleracea into the HCl-ethanol induced gastritis in rats, and to isolate and determine the chemical compounds from P. oleracea. Methods : The rats were orally administered with crude extract or fractions or isolated compounds of P. oleracea 30 mins before the induction of gastric lesion by oral administration of HCl-ethanol. The gastric lesional area was measured using pixel counting software. Then the chemical compounds from P. oleracea was isolated and determined by LC-MS and NMR. Results : The inhibition effect of oral administration of crude extract of P. oleracea at a dose of 500 mg/kg in HCl-ethanol induced gastritis was similar to cimetidine. Then, aqueous fraction at a dose of 240 mg/kg exhibited the effects similar to cimetidine. Then, the aqueous fraction was further separated by MPLC and yielded four sub fractions. Among those sub fractions, agent II at a dose of 40 mg/kg possessed the strongest effect in the HCl-ethanol induced gastritis. The water fraction yielded-Uridine, Adenosine, Guanosine, which were characterized by Mass, 1H-NMR, 13C-NMR. Conclusions : This study suggest that a P. oleracea and its compounds showed potent efficacy on the development of HCl-ethanol induced gastritis. Thus, P. olaracea can be a potential natural resource for the management of gastritis although the mechanism of action involved in the treatment remains to be explored.