The methodology of a retrospective study of the side-effects of the most prescribed lipid lowering drugs, essentially fibrates, is described. This study concerns the last 5-years reports to the French System of Pharmacovigilance, centralized in the common data-base located in Lyon. During this period 36 875 reports were recorded, only 409 in which an hypolipidemic drug is stated as "suspect" (according to WHO's definitions) were selected and analyzed. All fibrates were involved, those most frequently implicated being the most widely prescribed (e.g. fenofibrate represents half of the reports).