Up to the present time the diagnosis and treatment of chronic impairment of the liver in its early subclinical stages have not been practiced to any degree by the members of the medical profession. The main purpose of this communication is to outline a reliable and simple method for such early diagnosis, evaluation and treatment of chronic impairment of the liver in a stage prior to the appearance of clinical evidence. The fact that a relatively effective method is available for the treatment of acute or chronic impairment of the liver makes it especially important to detect and evaluate chronic hepatic impairment in its early stages, when intensive treatment may prevent the development of advanced chronic hepatitis and cirrhosis. Also, the recent development of much more sensitive tests now makes it possible in all probability to prevent the indefinite persistence in most cases of residual chronic hepatitis following acute hepatitis.