The objective of these investigations was to examine possibilities for preventing fatty liver in cows during the peripartal period using the preparation HEPARENOL which includes methionine, lysine and choline in its composition. Investigations were performed on cattle of the Holstein breed whose average production during their last lactation was 8120 liters. The cows included in the experiment were divided into three groups of 10 cows each. Cows of the first group were administered the preparation HEPARENOL perorally 5-7 days before partus in daily doses of 50 ml per animal, and then daily during the first seven days after parturition in daily doses of 100 ml per animal. The second group of cows were administered the preparation in the same way as the first group, but they also received vitamin C injected deep i.m. in doses of 1000 mg per animal per day. The third group of cows were not exposed to any treatment and served as the control group. The body condition of the cows was marked according to the system Elanco Animal Health Bulletin Al 8478. Blood samples were taken by puncture of the jugular vein before the beginning of treatment, and on the third and 12th days after partus. The glucose concentration was determined in the blood samples. On the 12th day after partus, liver tissue samples were taken by biopsy for pathohistological examinations. Since the cows were fed in the same way and were in the same phase of the production-reproduction cycle, the average score of the body condition before treatment was approximately the same. However, on the 3rd day after partus, cows of the second experimental group showed average values that were significantly lower in comparison with the other two groups of cows. It is very interesting that a significantly lower value of glycemia (x=1.93?0.34 mmol/l) was established in the same group of cows at this time. In cows of the first experimental and the control group, glycemia was approximately the same during the examined period. In cows of the second experimental group on the 12th day after partus the glucose concentration significantly increased (x=2.42?0.58 mmol/l) against the values obtained for the 3rd day, but it was still significantly lower in comparison with the glycemia of cows of the first experimental (x=3.34?0.61 mmol/l) and the control group (x=3.48?0.49 mmol/l). Practically, throughout the entire period glycemia was statistically significantly lower in the second experimental group in comparison with the other two groups of cows. The degree of fatty liver on the 12th day postpartally, or five days after the end of treatment, was the lowest in cows of the second experimental group. In order to stress the differences, it is pointed out that there were two cows without fatty liver in the second group, while there were no such cows in the first experimental or in the control group. This group contained the smallest number of cows with a mean degree of fatty liver (n=2), while two cows had very strong fatty liver. There were no differences between the control and the first experimental group in the number of cows with a mean degree of fatty liver, with the exception that the control group had two and the first experimental group one cow with a mild degree of fatty liver. It seems that treatment using the preparation HEPARENOL, or methionine, lysine and choline, before and after parturition did not have a significant effect on the incidence and degree of fatty liver. Only cows with additional and simultaneous treatment with vitamin C had a lower incidence and degree of morphological changes in the liver, in addition to the sigfnificant changes in body condition and the blood glucose concentration.