ObjectiveTo systematically review the clinical effectiveness and safety of middle and low-dose gamma globulin for severe idiopathic thrombocytopenic purpurar (ITP). MethodsDatabases such as The Cochrane Library (Issue 2, 2013), PubMed, EMbase, CBM, CNKI and WanFang Data were searched to collect randomized controlled trials (RCTs) involving the effectiveness and safety of middle and low-dose gamma globulin for severe ITP from the date of their establishment to July 2013. Two reviewers independently screened studies according to the inclusion and exclusion criteria, extracted data and evaluated the methodological quality of included studies. Then meta-analysis was performed using RevMan 5.2 software. ResultsEleven RCTs involving 548 patients were included. The trial group (n=272) were treated with middle and low dose of gamma globulin, while the control group (n=276) were treated with high dose of gamma globulin. The results of meta-analyses showed that there were no significant differences between the two groups in the total effective rate (RR=0.95, 95%CI 0.87 to 1.04, P=0.30), overall response rate (RR=0.97, 95%CI 0.85 to 1.10, P=0.60) and excellence rate (RR=0.94, 95%CI 0.78 to 1.14, P=0.54). The outcomes of time effect such as the time of platelet starting to rise and haemostasis time between the two groups was similar without significant differences. However, the control group was superior to the trial group in the peak time of platelet. The results of meta-analysis for platelet count of different periods showed that no significant differences were found in platelet count of 3, 7, and 14 days after starting the treatment, so do the peak of platelet count. No severe side effects were reported by both groups. ConclusionMiddle and low-dose gamma globulin could achieve the similar effect with the high-dose gamma globulin in the treatment of ITP. However, more high-quality, large-scale, RCTs are required to validate these results.