In a prospective trial of 75 Chinese patients with histologically proven inoperable hepatocellular carcinoma (HCC), 25 patients were randomised to receive doxorubicin 60-75 mg m-2 intravenously once every 3 weeks, 25 to receive recombinant alpha 2 interferon (rIFN) (Roferon) 9-18 x 10(6) IU m-2 intramuscularly (i.m.) daily and 25 to receive rIFN 25-50 x 10(6) IU m-2 i.m. three times weekly. Patients were switched to the other drug if: (a) there was progressive disease after 12 weeks, (b) unacceptable toxicity developed and (c) they had received a total of 500 mg m-2 of doxorubicin. Six patients had switching over of therapy, three on doxorubicin and three on rIFN. In the remaining 69 patients on single drug therapy, the median survival rate of patients on doxorubicin and rIFN was 4.8 and 8.3 weeks respectively (P = ns.). rIFN induced tumour regression of 25-50% in 12% of patients and of over 50% in 10% of patients. When compared with doxorubicin, rIFN was associated with more tumour regression (P = 0.00199) and less progressive tumours (P = 0.00017). It caused less prolonged and less severe marrow suppression (P = 0.01217), and had significantly less fatal complications than doxorubicin (P = 0.01383). Doxorubicin caused fatal complications due to cardiotoxicity and neutropenia in 25% of patients. rIFN was associated with fatal complications due to dementia and renal failure in 3.8% of patients. In the treatment of inoperable HCC, rIFN is superior to doxorubicin in causing more tumour regression, less serious marrow suppression and less fatal complications.