Objectives: Gastric ulcer is a chronis disease with a lot of dangerous complications and H. pylori is a major cause of gastric ulcer. Eradicating H. pylori helps reducing ulcer relapse and preventing cancer. The aim of study: to evaluate the rate of H. pylori infection in gastric ulcer and efficacy of quadruple therapy RACM for 5 days in patients with gastric ulcer with H. pylori positive. Materials and methods: Total 98 patients with gastric ulcer have been performed the endoscopy and CLO-Test, treated with quadruple therapy RACM for 5 days and evaluate efficacy 4 weeks after ending treatment. Results: The rate of H. pylori in gastric ulcer is 82.65%. The rate of H. pylori eradication is 88.71%. The effect of reducing pain of therapy is 90.32%; and the rate of reducing pain: 96.37% in successfully H. pylori-eradicated group and in the other group 42.85% (p < 0.05). The effect of healing ulcer of therapy is 77.41%; and the rate of healing gastric ulcer: 83.63% in successfully H. pylori-eradicated group and in the other group 28.57% (p < 0.05). The adverse effects of therapy included tiredness: 11.29%, lose appetite: 8.06% and diarrhea: 6.45%. Conclutions: Quadruple therapy RACM for 5 days showed an effective, safe and simple regime for eradicating H. pylori and should be considered to apply as the first lines treatment for H. pylori.