Objectives:To evaluate the efficacy and safety of azithromycin injection compared with clarithromycin in the treatment of acute bacterial infections. Methods: A total of 160 patients were included in this study, 60 cases of respiratory infections treated with azithromycin were compared with 60 cases treated with clarithromycin, 40 cases of other tissue infections were treated with azithromycin. Drugs were administered intravenously once daily (for azithromycin) or twice daily (for clarithromycin) for 5~7 days, at a daily dose of 0.5 g of azithromycin or 1.0 g of clarithromycin. Results: The overall clinical efficacious rates of azithromycin was 92.0%. There was no significant difference( P 0.05) between azithromycin and clarithromycin in the clinical efficacy and bacterial clearance rates. The incidence of adverse drug reactions for azithromycin (15%)was lower than that for clarithromycin(45.0%, P 0.05 ). Conclusions: Azithromycin injection is an effective and safe antibiotics for the treatment of bacterial infection.