SummaryThe aim of the study was the assessment of the impact of supplementation with folic acid on the concentration of homocysteine, total cholesterol (TC), HDL-and LDLcholesterol, triglycerides (TG), apoprotein AI (apoAI) and apoprotein B (apoB) in patients suffering from primary hypertension. The examined group comprised 42 patients suffering from primary hypertension. All examined patients underwent laboratory tests as follows: concentration of homocysteine, folic acid, TC, LDL-cholesterol, HDL-cholesterol, TG, apoAI and apoB. All patients were orally administered with 15 mg of folic acid per day for 45 d. After this period, all laboratory tests were repeated. Homocysteine concentration was measured by the FPIA method, concentrations of apoAI and apoB were measured by the nephelometric method, and other parameters with routine methods. After administration of 15 mg of folic acid to patients with primary hypertension, a considerable decrease in the concentration of homocysteine was observed in parallel with a substantive growth of HDLcholesterol, as well as apoprotein AI concentrations and a reduction of the apoprotein B concentration. Results of statistical analysis indicated a significant correlation between the decline in homocysteine concentration and the increase in HDL-cholesterol concentration, as well as between the increase of folic acid concentration and the increase in apoAI concentration in patients following the intake of folic acid. The drop in homocysteine concentration through the supplementation with folic acid can cause quantitative changes in the lipid and lipoprotein parameters which, in consequence, may lead to the mitigation of risk concerning the development of atherosclerosis. Key Words hypertension, hyperhomocysteinaemia, cholesterol, triglycerides, apoproteins Hypertension is one of the most common symptoms of cardiovascular diseases. Ninety percent of affected patients are diagnosed with primary hypertension. The etiology of this disease includes numerous genetic, environmental and neuro-hormonal factors, which often co-exist and are linked one to another. Due to that fact, hypertension is frequently accompanied by metabolic disorders such as obesity, diabetes, and hyperlipidaemia. These diseases are often also accompanied by mild chronic inflammation, disorders of the coagulation system and fibrinolysis, as well as hyperhomocysteinaemia. Some of the cardiovascular disease risk factors may be modified through a change in lifestyle and medication. The positive impact of modified standard risk factors, such as disturbances in lipid and carbohydrate metabolism disorders, as well as obesity, is relatively well documented.As far as hyperhomocysteinaemia is concerned, studies on its importance in the development of hypertension, as well as on the impact of its treatment in eliminating the risk of cardiovascular diseases, are still being carried out. High blood pressure is often accompanied by hyperhomocysteinaemia. High level of homocysteine could adversely affect the synthesis and bioacc...