Abstract: Objective The aim of this study is to evaluate whe the rN-acety ltransferase-2 acetylator phenotype is associated with antituberculosis drug-induced hepatotoxicity in Chinese patients.Methods A total of 187 patients with newly diagnosed tuberculosis and antituberculosis treatment was followed prospectively for six months.The patients received liver function tests periodically.Patients(n=36)did not develop hepatotoxicity were selected to match each case,and their NAT2 genotypes were determined by the PCR-restriction fragment length polymorphism method.Results 19.46% of patients developed antitube rculosis drug-induced hepatotoxicity.There was a 4-fold risk of hepatotoxicity for the slow acetylators compared to the rapid acetylators(adjusted χ²=4.27,P<0.05;OR=4.00,95%CI=1.07-14.91).Conclusion Slow acetylator status of NAT2 was a significant susceptibility risk factor for antituberculosis drug-induced hepatototxicity and NAT2 genotyping may be a useful tool for predicting antituberculosis drug-induced hepatotoxicity.