The aim of this study was to establish the efficacy of treating chemically induced, autochthonous liver cancer by locoregional administration of cytostatics. Hepatomas were induced by p.o. application of diethylnitrosamine (15 mg/kg/week X 25 weeks) in female SD-rats and were staged macroscopically at four weeks after the end of the induction period. For treatment, catheters were inserted into the proper hepatic artery (i.a.) or the vena cava (i.v.) and tumor-bearing rats received a course of either mitomycin C (1 mg/kg i.a. within 24 hours), of mafosfamide (40 mg/kg i.a. within 4 hours) alone or in combination with sarcosinedithiocarbamate (300 mg/kg i.v. within 4 hours) or of triglycidylurazol (40 mg/kg i.a. or 20 mg/kg i.a. within 4 hours). At 14 days later no spontaneous repression of hepatomas were observed in the control animals, but 27% to 78% of treated animals showed a positive response. This response, however, was shortlived and did not lead to a significant prolongation of the animals life span in comparison to sham-treated controls.