The biodegradation of collagen is a process of a vital importance both in norm and in pathological conditions. The initial stage in the collagen degradation is an extracellular proteolytical process, started up by the collagenases – Zn-dependent metalloenzymes, that break up the collagen specifically. In normal liver the collagenase activity was determined in Kuppfer cells. In experimental fibrosis an evident increase of its activity was observed in fibroblasts, Ito cells and hepatocytes. In advanced or irreversible liver cirrhosis the activity of the colagenase decreased. During the recovery from hepatic fibrosis an increase of collagenolytical activity and a decrease of collagen quantity were determined.