In the beginning of this century a possible relation was observed between cholesterol-rich foods, blood cholesterol levels and atherosclerosis by "pioneers" in this field as Anitschkow and De Langen. In the second half of this century a definite link was established between serum cholesterol levels and development of coronary heart disease (CHD). In angiographic studies it has recently been shown that a decrease in total cholesterol as well as in low-density lipoprotein cholesterol level results in a retardation of the progression of vascular disease. Furthermore, clinical event intervention trials demonstrated that therapy with cholesterol synthesis inhibitors reduces not only cardiovascular and total mortality, but also other manifestations of CHD. These recent results prompted to revise, for the second time, the Dutch consensus text for lipid lowering therapy, with the following conclusions. Hypercholesterolaemia is treated with a low-saturated fat diet and normalisation of weight. For individuals, this might result in a reduction of the risk for myocardial infarction or death and for the population in a decrease of the mean serum cholesterol concentration and a reduction of the incidence of CHD. The indication for drug therapy is founded on the expected effectiveness to reduce the incidence of (new manifestations of) CHD, which is related to the level of the absolute risk of vascular disease. Treatment with cholesterol synthesis inhibitors must be considered in (a) patients with familial hypercholesterolaemia; (b) all patients with a history of myocardial infarction or other symptomatic vascular disease with a total cholesterol concentration above 5.0 mmol/l and a life expectancy of at least five years; (c) persons without known vascular disease with a combination of diabetes mellitus, hypertension, hypercholesterolaemia, cigarette smoking and high risk for development of CHD, rising from 25% per 10 years at the age of 40 years to 35-40% per 10 years at the age of 70 years, with a life expectancy of at least five years. If these guidelines are followed, the calculated cost-effectiveness is about Dfl. 40,000 per life year gained or less. The consensus committee judges this reasonable in comparison with other therapeutic interventions in the Netherlands. Thus by now, with regard to lipids and atherosclerosis, the definite link has been established between observational medicine and an effective treatment modality which is applicable in daily practise.