The symptoms and clinical course of repeated poisonings with isopropyl alcohol in ethanol addicted 43-years old man is presented in the study. The blood and urine concentrations of isopropanol and acetone and also the blood ethanol concentration are given. The biological half-life of isopropanol calculated for the first 12 hours from admission to the Clinic was 6.9 hours. The biological half-life of acetone in the first 6 hours of hospitalisation was 5 hours, and then a considerable slowing down up to 29 hours was noted. The clinical symptoms, similar to ethanol poisoning, including strongly manifested catatonia and ketonuria without metabolic acidosis indicate the isopropanol intoxication. Hypokalemia should to be taken into consideration in treatment of isopropanol poisoning. An intravenous bicarbonates should be administered carefully e.g. when rhabdomyolysis occur.