Forty-four male and female subjects aged 22-57 years were studied. Thirteen patients had acute viral hepatitis, and eleven patients had cholestatic jaundice due to carcinoma of the head of the pancreas. Twenty healthy volunteers who served as controls were also included. In hepatitis patients, the mean plasma levels of total cholesterol (TC) and the high density lipoprotein (HDL)-phospholipid/phospholipid (HDLPL/PL) ratio were reduced, and HDL-cholesterol (HDLC), HDL-phospholipid (HDLPL) and the phospholipid/total cholesterol (PL/TC) ratio were normal, while total phospholipid (PL) levels and the HDLC/TC ratio were significantly increased compared to the control values. In patients with cholestatic jaundice the mean plasma total cholesterol, phospholipid and HDLC levels were elevated, and HDLPL/PL, HDLPL, HDLC/TC and PL/TC remained normal compared to the control values. A comparison within the patient groups showed that plasma TC, PL and HDLC levels were significantly increased in cholestatic jaundice when compared with the corresponding levels in hepatitis patients. The mean plasma levels of HDLPL, HDLC/TC and PL/TC did not show any significant variation within the patient groups. Alkaline phosphatase (ALP) correlated positively with TC, and total protein correlated negatively with TC and HDLPL, while albumin correlated negatively with TC, HDLC and HDLPL in cholestatic jaundice. Alanine amino-transferase (ALAT) also correlated positively with PL in cholestatic jaundice, while albumin correlated positively with TC in hepatitis. The results suggest that lipoproteins might be metabolized differently in these two forms of cholestasis.