Experiments were conducted on male rats. A study was made of the content of nicotinamide coenzymes in the liver and myocardium 24 hours after the administration of 0.5 ml of dichloroethane into the stomach. In parallel with disturbance of the morphological structure of the liver and of the myocardium, increase in the activity of alanine and aspargic aminotranspherases in the blood serum, dichloroethane reduced the content of nicotinamide coenzymes and deranged the ratio of their oxidized and reduced forms in these organs.