Aims: To assess efficacy and safety of HMG-CoA reductase inhibitor (statin) treatment in children and adolescents with heterozygous familial hypercholesterolaemia. Methods: MEDLINE, EMBASE, COCHRANE and Current Controlled Trials databases were searched. Study design, efficacy, and safety outcome-measures were extracted. Results of parallel-group randomised placebo controlled trials with low density (LDL) and high density lipoprotein cholesterol (HDL), and triglycerides as outcomes were pooled using standard meta-analytical methods. Results: One hundred and fifty seven of 1060 identified papers studied familial hypercholesterolaemia, and 18 papers reported 7 prospective case series, 1 non-randomised trial, 2 trials with active treatment control groups, and 8 parallel-group randomised placebo controlled trials (RCT). The RCTs randomised 947 children, aged 8-18 years, for periods of 6-96 weeks with an estimated 850 person-years follow-up. There were no differences in clinical or laboratory adverse reactions between placebo and active treatment. Statins lowered LDL 32.5% (95% CI 24.3, 40.7), increased HDL 3.4% (0.8, 6.0), lowered triglycerides 3.0% (-11.6, 17.6), attenuated progression of carotid medial thickness, and improved endothelial function. Conclusions: Statin monotherapy is efficacious, well tolerated and safe in the short-term, although long-term safety remains unclear. Current evidence supports treatment of children at highest cardiovascular risk, but results of on-going, longer-term studies may extend these indications. (C) 2006 Elsevier Ireland Ltd. All rights reserved.