We studied the first degree relatives of gastric cancer patients , aged 40_65 years old, who had gastritis but no peptic ulcer in endoscopy. Their gastritis didn’t limit to antrum. Six locations in stomach (lesser curvature_ mid antrum, lesser curvature_ angulus, lesser curvature_ mid body, grater curvature_mid antrum, grater curvature_ angulus, grater curvature _mid body) were biopsied. Patients with precancerous lesions and helicobacter pylori infection were entered into study. from 1020 patients, 480 patients who were entered, were divided into two groups randomaly. 240 patients as case group treated with 500mg Amoxicillin, 20mg Omeprazol, 240 mg Bismute and 500 mg Metronidazol, twice a day, for 2 weeks. 240 patients as control group treated with placebo. Patients were observed with UBT for helicobacter pylori eradication 6_8 weeks later and endoscopy were done for them after one year. Two groups (case_ control) were compared for cancerous lesions after a year.