As is known, the liver in the body of mammalian animals converts nutrients into other chemical formations, which are later used by the body itself or are excreted. Also, this organ performs a detoxification function. The liver contains the necessary supply of blood, vitamins and carbohydrates for the animal, as well as the synthesis of some blood proteins and other vital organic substances. It is known that up to 1,000 different biochemical processes take place in this largest gland of the body, however, due to the enormous load on the hepatocyte, it often undergoes destruction. The level and intensity of metabolic processes in the body of animals depends on the morphofunctional state of this organ. The aim of the research was to study the spread and manifestation of hepatopathy in monogastric animals in the conditions of the Northern Trans-Urals. The liver of the studied animals (rabbits and dogs) was selected for morphohistological studies. Based on the conducted studies and analysis of the results obtained, it was found that various types of hepatopathy in rabbits with unbalanced feeding and feeding with substandard feed were observed in 45% of cases, and in dogs - in 41.7% of cases. For the digestive glands, both substandard commercial feed and feed prepared by the owners of animals themselves have a negative impact. At the same time, the degree of liver dysfunction did not depend on whether the animals were fed industrial feed or food "from the table". In the course of our research, the following data were obtained: during morphological examination of the liver of rabbits, pathologies were established in 45% of cases, of which hydropic dystrophy -10%, hepatosis -20%, cirrhosis -15%. Liver dysfunction, as an independent disease, was registered in dogs in 14.1% of cases. In experimental dogs, we treated the following types of liver lesions: 42% - liver steatosis, 24.5% - liver inflammation, 12% - liver cirrhosis, 19.2% - cholecystitis, 2.3% - liver neoplasms.