Partial hepatectomy of mouse cirrhotic liver leads to rapid degeneration of hypertrophied connective tissue. Enlarged cisterns of the smooth endoplasmic reticulum lie close to the plasma membrane on the sinusoidal surface of hepatocyte. Golgi apparatus of Kupffer cells is hypertrophied, swollen collagen fibrils lose their specific striation. Microvilli of hepatocyte plasmalemma separate swollen collagen fibrils and draw them into the cytoplasm. Lysosomes, peroxisomes, and hypertrophied Golgi apparatus are spread from the sinusoidal surface to bile capillaries, which indicates that these structures are involved in collagen lysis and release of metabolites into the bile capillary. After partial hepatectomy of cirrhotic liver, hepatocytes, Kupffer cells, and neutrophils play the major role in collagen lysis. Kupffer cells and neutrophils are involved in the lysis of collagen fibrils during CC14-induced liver cirrhosis.Key Words: hepatocyte; Cfl4, collagen degradation A large body of data suggests reversibility of sclerotic changes in organs. It was shown that under certain conditions, hypertrophied fibrous tissues in the liver undergo degeneration [27,34]. Light microscopy demonstrated regeneration of cirrhotic liver after termination of CC14 poisoning [ 18], and partial hepatectomy accelerates this process [22].Changes in collagen fibrils, hepatocytes, and Kupffer cells (KC) in cirrhotic liver, formation of regeneration hepatomas, and regeneration of sclerotic liver after termination of CCI~ poisoning and partial hepatectomy were studied by electron microscopy. Liver cirrhosis in mice was induced by administration of 0.2 ml 40% CC14 in peach oil 2 times a week for 13 months. The left hepatic lobe was removed 5 months after the start of CC14 poisoning to study collagen resorption and to identify cells involved in this process.