In an observational study in general and internal medicine practices, 5000 patients were treated over a mean of 8 to 9 weeks with fluvastatin. The lipid-lowering effect and tolerability of the preparation were documented. The participating patients had a mean age of 56.1 years, 46.7% were female and 53% were male. 62.9% of patients had primary hypercholesterolaemia, and 37.1% had combined hyperlipidaemia. At the end of the study, 44.2% of patients were taking 20mg fluvastatin, and 55.5% of patients 40mg fluvastatin. The cholesterol level fell by a mean of 27.2%, the LDL cholesterol level by 38.1%. The HDL cholesterol level increased by a mean of 27.3%. The triglyceride level fell by a mean of 8.6% in the group with primary hypercholesterolaemia, and by 20.3% in the group with combined hyperlipidaemia. On subgroup analysis, the efficacy showed no dependence upon age, gender, concomitant conditions or concomitant medications. Adverse drug effects occurred in only 2% of patients, and caused withdrawal of treatment in only 17 patients (0.34%). Almost 80% of investigators rated therapy with fluvastatin as very good, 19.3% as satisfactory and only 1% as unsuccessful. Fluvastatin is an effective and well tolerated preparation for lowering lipid levels under routine practice conditions, and thus considerably reduces the atherosclerotic risk of treated patients.