All types of hyperlipoproteinaemia must be corrected to prevent or delay the atheroma they produce, or even bring about its regression. A dietetic regimen is prescribed first to be completed, if necessary, by a medicinal treatment. Once instituted, these treatments must be pursued indefinitely, the return to normal lipid levels being a sign of their effectiveness and not a reason for their discontinuation. Conversely, failure to obtain normal lipid levels indicates that the treatment should be modified, especially the dietetic regimen which, when not regularly adhered to, often is the cause of resistance of hyperlipoproteinaemia. One must watch for iatrogenic complications in order to detect and prevent them. The drugs most frequently prescribed for hypercholesterolaemia are resins that absorb biliary acids, fibrates, probucol and, very soon, HMG coareductase inhibitors, and for mixed hyperlipidaemia and hypertriglyceridaemia, fibrates and, accessorily, nicotinic acid.