Endothelial cells lining the vascular vessels determine intravascular homeostasis. Dysfunction of these cells results in rise of the intravascular inflammatory reaction, clotting of blood with simultaneous impaired fibrinolytic plasma activity. All these disorders predispose to progression of atherosclerosis in arteries or de­velopment of the thrombotic diseases in veins. Sulodexide is a mixture of glycosaminoglycans: heparin and dermatan sulphate, which on one hand suppresses the intravascular inflammation and on the other hand have protective effect towards the endothelium. Sulodexide reduced cytotoxicity of hyperglycemia towards endothelium and also suppresses the intracellular oxidative stress and inflammation in the endothelial cells, what results in their slower senescence. Sulodexide also lowers the blood level of lipids, what reduces toxic­ity of plasma towards the endothelial cells. All listed effects of sulodexide may explain its effectiveness in therapy in a group of patients with the cardiovascular disorders. Treatment with that drug results in reduction of thrombotic and ischemic complications in patients with myocardial infarction. Sulodexide improves also peripheral vascular blood flow in patients with peripheral arteries diseases or in patients with chronic thrombotic venous diseases. Components of sulodexide are naturally present in the human organism, ie. as components of the glycocalix covering the surface of the endothelial cells and that fact may explain a good tolerance of that drug by patients.