Determination of serum bile acids has long been regarded as the most sensitive indicator of liver function. An assessment was made of the clinical applicability of RIA evaluation of two of these acids, cholylglycine (CG) and sulpholithochocholyglycine (SLGG), on an empty stomach and 2hr after a cholecystokinetic meal in 109 liver patients ans 20 controls. After the meal test, both acids proved more sensitive than the usual liver function indices. Different mean values were observed for different diseases. They were in good correlation with the extent of histological damage. Values were highest in obstructive icterus, cirrhosis and neoplasia of the liver, fairly highly high in steatofibrosis, ACH and PCH, and normal in viral hepatitis in the course of resolution, aspecific reactive hepatitis, and steatosis. The meal test thus proved a good indicator of liver disease. Its wider use is to be hoped for in order that its limits and applications may be better understood.