Atherogenesis is the result of interactions of factors originating from blood stream and the reaction of the arterial wall. Basing on this we have a pathogenetic trias: blood--lining membrane--arterial wall. Under these aspects some modern trends of experimental research are discussed. An example of blood-plasmatic injury is the hyperlipidaemia. The permeability of the lining endothelium regulates the infiltration and is influenced by several factors. The reactions of the modified smooth muscle cells in the arterial wall are the most important events in early atherogenesis. The metabolic decompensation of these cells is a main factor in the transition to advanced lesions. The efficiency of the cells is the preliminary condition for the reversibility of atherosclerotic lesions. Only early stages have some chances of regression; one must bear in mind this together with all therapeutical treatments.