Objective To assess the efficacy and safety of S-adenosyl-l-methionine (SAMe) for outcome improvement of intrahepatic cholestasis of pregnancy. Methods Randomized controlled trials (RCT) and quasi-randomized controlled trials were identified from MEDLINE (1983 to 2003), The Cochrane Library (Issue 4,2003), EMBASE (1980 to 2003), China Hospital Digital Library (CHDL) and Wanfang data (1994 to 2003). We also handsearched the relative references. Two researchers evaluated the quality of the trials and extracted the data independently. RevMan software 4.2 was used for meta-analysis. Results Eight studies involving 424 pregnant women were included. The following data were the results of meta-analysis of SAMe for improvements: ① Reducing cesarean-section ratio: no significant difference was seen between SAMe and placebo groups with OR 1.00, 95%CI 0.23 to 4.33 and P= 1.00; significant differences were seen SAMe versus dexamethasone and SAMe versus Dianglining with OR 0.44, 95%CI 0.23 to 0.85 and P=0.01; OR 0.28 95%CI 0.10 to 0.75 and P=0.01 respectively。② Prolonging the period of pregnancy: SAMe had no significant difference compared with placebo groups with WMD=0.70, 95%CI －0.69 to 2.10, P=0.32. SAMe was more effective than dexamethasone, Ganyinling and Qianglining on prolonging the period of pregnancy with WMD=1.10，95%CI 0.46 to 1.74, P=0.000 07; WMD=2.50，95%CI 1.86 to 3.14, P≤0.000 01; WMD=2.20，95%CI 1.61 to 2.79, P≤0.000 01 respectively；③ Increasing the weight of the newborn: meta-analysis showed that SAMe group had not significant difference compared with placebo group on increasing the weight of the newborn with WMD=-26.27，95%CI -338.35 to 285.82, P=0.87. Significant differences were seen between SAMe and dexamethasone, SAMe and Ganyiling, SAMe and Qiangling with WMD=386.86，95%CI 134.41 to 603.31, P=0.002; WMD=410.00,95%CI 321.10 to 498.90, P≤0.000 01 respectively. ④ Fetal distress: There was no significant difference compared with dexamethasone and Kuhuang groups on decreasing the fetal distress with OR=0.47, 95%CI 0.14 to 1.16, P=0.23; OR=0.44, 95%CI 0.10 to 1.97, P=0.29 respectively; ⑤ Decreasing pollution of amniotic fluid: no significant differences were seen in SAMe versus dexamethasone, SAMe versus ursoddeoxycholic and SAMe versus Kuhuang with OR=0.46, 95%CI 0.21 to 1.02, P=0.06; OR=0.68, 95%CI 0.20 to 2.31, P=0.53; OR=0.82 95%CI 0.24 to 2.81,P=0.75 recpectively. ⑥ Newborn stifile: SAMe group had no significant difference compared with dexamethasone and Kuhuang groups on decreasing the Newborn stifile with OR=0.19, 95%CI 0.01 to 4.06, P=0.29; OR=0.31, 95%CI 0.08 to 1.13, P=0.08 respectively. Compared with Qianglining group, SAMe group had better effect on reducing ratio of newborn stifile with OR=0.09, 95%CI 0.02 to 0.42, P=0.002. ⑦ Improving Apgar scores: no significant differences were seen between SAMe and placebo, dexamethasone and ursoddeoxycholic with OR=0.25, 95%CI 0.02 to 3.04, P=0.28; OR=2.09, 95%CI 0.70 to 6.27, P=0.19; OR=1.22, 95%CI 0.35 to 4.19, P=0.75 respectively. Six RCTs mentioned the side effects of S-adenosy-l-methionine, only one RCT reported mild gastrointestinal irritation. Conclusions SAMe is partly effective on improving the pregnancy outcomes of intrahepatic choletasis of pregnancy, such as reducting cesarean-section ratio, prolonging the period of pregnancy and increasing the weight of the newborn. The specified efficacy and safety of SAMe require rigorously designed, randomized, double-blind and placebo-controlled trials to offer evidence.