Clearance refers to the disappearance of HP at the end of drug therapy, and eradication refers to no recurrence of HP for at least 4 weeks after the end of drug therapy. Clinically, it is required to achieve HP eradication, and the recurrence rate of chronic gastritis and peptic ulcer can be greatly reduced. In vitro drug sensitivity test showed that under neutral pH conditions, HP is most sensitive to penicillin, highly sensitive to aminoglycosides, tetracyclines, cephalosporins, ofloxacin, cloxacin, erythromycin and rifampin; moderately sensitive to macrolides, furans and chloramphenicol; highly resistant to vancomycin, but HP is moderately sensitive to bismuth salts. Urea breath test with endoscopy plus histological examination positive for H. pylori can be used in triple therapy of omeprazole, amoxicillin, metronidazole 0.2, and other antibiotics such as tetracycline, erythromycin, gentamicin, clarithromycin, etc. for positive penicillin test. The principles for the selection of treatment regimens are: ① the use of a combination of drugs, such as triple therapy or quadruple therapy, which is commonly used internationally; ② the eradication rate of H. pylori > 80%, preferably above 90%; ③ no significant side effects, well tolerated by patients; ④ the economic affordability of patients. The effectiveness of treatment for H. pylori infection should be judged by the eradication rate of H. pylori, not the clearance rate. Eradication is defined as the absence of bacterial growth confirmed by bacteriological, pathological histological or isotopic tracing methods at least one month after the termination of treatment.