Paradoxical growth hormone (GH) responses in 50 g or 75 g oral glucose tolerance tests (OGTT) have been demonstrated in 24 patients with hepatocellular carcinoma, whereas no significant changes in serum GH levels after OGTT were shown in 10 normal controls, 6 patients with cirrhosis of liver, and with chronic active hepatitis. There were no significant difference in the GH responses in OGTT as well as in the incidence of paradoxical GH responses between diabetic and non-diabetic patients with HCC. Informatively, the basal somatomedin C level was very low in all cases examined.