An elevated concentration of low-density-lipoprotein cholesterol (LDL-C) plays a causal role in the development of coronary heart disease and ischaemic stroke. Placebo-controlled intervention studies of statin drugs for lowering LDL-C provide clear evidence of cardiovascular disease prevention. LDL-C concentration below 2.5 mmol/L is an arbitrary goal, and recent trials support the benefit of achieving this goal, or even lower levels. Pharmacological treatment is warranted in patients with high absolute risk of future cardiovascular events. Effective monotherapy is available for predominant hypercholesterolaemia and predominant hypertriglyceridaemia, but combination therapy may be required for severe cases or in those with mixed hyperlipidaemia. Side-effects are infrequent and usually mild, but widespread use of lipid-modifying medication demands caution because of the possibility of muscle or liver dysfunction or drug interactions.