Abstract: The paper presents the results of experimental therapy of precancerous andcancerous lesions of forestomach of mice.Oolong tea,Which was form high incidencearea of esophegeal cancer,Shantou,showed inhibitory effect on carcinogenesisof forestomach of mice induced by NSEE(nitrososarcosin ethyl ester).After beingtreated by Oolong tea,the cancerous rate droped from 64.8% to 25.0%.Oologn teahadn't toxic and side-effect on the meice.