Objective To evaluate systematically the effectiveness and safety of procalcitonin ( PCT) -guided therapy in comparison with standard therapy in patients with suspected or confirmed severe bacterial infections in intensive care unit ( ICU) . Methods Five randomized controlled trials ( 927 patients) were included for statistical analysis by the cochrane collaboration′s RevMan5. 0 software. Results PCT-guided therapy was associated with a significant reduction in duration of antibiotic therapy [ MD =- 2. 01, 95% CI ( - 2. 37, - 1. 64) , P lt;0. 00001] , but the mortality [ OR =1. 11, 95% CI ( 0. 83, 1. 49) ,P =0. 47] and length of ICU stay[ MD = 0. 49, 95% CI( - 1. 44, 2. 42) , P = 0. 62] were not significantly different. Conclusions An algorithmbased on serial PCT measurements would allow a more judicious use of antibiotics than currently traditional treatment of patients with severe infections in ICU. It can reduce the use of antibiotics and appears to be safe.