The authors review the pathomechanism and frequency of side effects (myopathy and rhabdomyolysis) of the lipid lowering agents, statins and fibrates, on the basis of large prospective studies. They review in detail the possible pathomechanism of myopathy as caused by statins and fibrates. The cytochrome P450 enzyme system plays a role in the interaction of other drugs with long term statin therapy. The long term administration of statin and fibrate to patients with primary and secondary hyperlipidemia was considered safe on the basis of our experience and literature data. The combination of statin and fibrate is also considered safe and useful in the treatment of combined hyperlipidemia. As a precautionary measure, we emphasize the ruling out of liver, kidney and muscular diseases in such patients. Lipid lowering therapy is efficient in the primary and secondary prevention of cardiovascular diseases if applied cautiously.