Ultrasonic tissue classification (ultrasonic spectroscopy) utilizes tissue specific information, which is only partially processed in conventional B image ultrasound, to calculate several acoustic tissue parameters (e.g. frequency dependent attenuation, frequency slope of attenuation, relative backscatter). The use of these acoustic tissue parameters for qualitative and quantitative tissue differentiation was examined in liver tissue of 35 carbon tetrachloride intoxicated and 16 healthy rats in this study. Furthermore several liver specific laboratory parameters were determined and histological tissue examinations of all livers were performed. Only the relative backscatter, the histological tissue examination and certain laboratory parameters (aspartate and alanine aminotransferase, prothrombin time, antithrombin III, albumin, bilirubin) provided a significant differentiation between normal and diseased liver tissue. However, none of the methods examined in this study allowed for a precise and reproducible quantitative evaluation of the degree of tissue damage.