IntroductionHydroxyethyl starch (HES) has been widely used for volume expansion, but its safety in adult patients has been questioned recently. The aim of this meta-analysis is to see whether or not HES has any adverse effect in pediatric patients.MethodsRandomized controlled trials (RCTs) involving pediatric patients who received 6% low-molecular-weight HES, published before January 2014, were searched for in Pubmed, Embase database and Cochrane Library. Two reviewers independently extracted the valid data, including the mortality, renal function, coagulation, blood loss, hemodynamic changes, and length of hospital and ICU stay. All data were analyzed by I2-test, and the results of statistical analysis were displayed in forest plots. Possible publication bias was tested by funnel plots. Bayesian analysis was performed using WinBUGS with fixed and random effects models.ResultsA total of 13 RCTs involving 1,156 pediatric patients were finally included in this meta-analysis. Compared with other fluids, HES did not significantly decrease the mortality (RR = -0.01; 95%CI: 0.05 to 0.03; P = 0.54; I2 = 6%), creatinine level (I2-test: MD = 1.81; 95%CI: -0.35 to 3.98; P = 0.10;I2 = 0%; Bayesian analysis: Fixed effect model MD = 1.77; 95%CI: -0.07 to 3.6; Random effects model MD = 1.78; 95%CI: -1.86 to 5.33), activated partial thromboplastin time (MD = 0.01; 95%CI: -1.05 to 1.07; P = 0.99; I2 = 42%), and blood loss (MD = 17.72; 95%CI: -41.27 to 5.82; P = 0.10; I2 = 0%) in pediatric patients. However, HES significantly decreased the blood platelet count (MD = 20.99; 95%CI: -32.08 to -9.90; P = 0.0002; I2 = 28%) and increased the length of ICU stay (MD = 0.94; 95%CI: 0.18 to 1.70; P = 0.02; I2 = 46%).ConclusionsVolume expansion with 6% HES significantly decreased the platelet count and increased the length of ICU stay, also might have an adverse effect on renal function. Therefore HES is not recommended for pediatric patients, which safety needs more high quality RCTs and studies to confirm in future.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0815-y) contains supplementary material, which is available to authorized users.