An effective eradication therapy of Helicobacter priori (H.pylori) should be used for the first time.In this study,we assessed whether tailored therapy based on antibiotic susceptibility testing is more effective than traditional therapy.We also evaluated the factors that cause treatment failure in high-resistance areas.For this multicenter trial,we recruited 467 H.priori-positive patients.The patients were randomly assigned to receive tailored triple therapy (TATT),tailored bismuth-containing quadruple therapy (TABQT),or traditional bismuthcontaining quadruple therapy (TRBQT).For the TATT and TABQT groups,antibiotic selection proceeded via susceptibility testing using an agar-dilution test.The patients in the TRBQT group were given amoxicillin,clarithromycin,esomeprazole,and bismuth.Successful eradication was defined as a negative 13C-urea breath test at least eight weeks after the treatment ended.Susceptibility testing was conducted using an agar-dilution test.The eradication rate was examined via intention-to-treat (ITT) and per-protocol (PP) analyses.The claritbromycin,levofloxacin,and metronidazole resistance rates were 26.12％,28.69％,and 96.79％,respectively.Resistance against amoxicillin and furazolidone was rare.The eradication rates for TATT,TRBQT,and TABQT were 67.32％,63.69％,and 85.99％ in the ITT analysis (P ＜ 0.001) and 74.64％,68.49％,and 91.22％ in the PP analysis (P ＜ 0.001),respectively.The efficacy of TABQT was affected by clarithromycin resistance,and bismuth exerted a direct influence on TATT failure.TABQT was the most efficacious regimen for use in high-resistance regions,especially among clarithromycin-susceptible patients.