Determination of the total biological eff ects of anthropogenic water pollution remains an important issue. Our long-term studies have shown that numerous alterations occur in the frog liver histological structure under pressure of anthropogenic pollution factor. The leukocyte infi ltration, fat dystrophy, protein dystrophy and necrosis are well known on the mammal liver. Also we first described the rebuilding in the normal liver structure and the depletation of the fibrous tissue which are characteristic for the amphibians. Quantitative analysis of these alterations can identify signifi cant differences in the pattern of pathological changes in the liver of the green frogs, which pick up in anthropogenically contaminated landscapes and in the clear ponds. Th is method allows quantifying the degree of biological eff ect of pollution.