Liver diseases are a major focus of research in the Faculty of Veterinary Medicine. In a clinical population 1% of the dogs has a form of hepatitis. There are several aspects of canine hepatitis which make comparison with human hepatitis very useful. As a whole, liver diseases and especially different forms of hepatitis in dogs develop highly similar to human hepatitis (fulminant, acute, chronic). This makes dog diseases interesting to study important aspects in the pathogenesis of the disease. We have shown that in humans and dogs identical processes with respect to formation of fibrosis, regeneration, stem cell activation, and oxidative damage occur. In most aspects identical pathogenesis and pathophysiology of canine and human hepatitis make these spontaneous dog diseases ideal models to study the effect of new modes of intervention to stimulate regeneration and reduce or prevent cirrhosis.