To determine the effect of coadministration of lipiodol on the pharmacokinetics and systemic toxicity of intraarterial Adriamycin in patients with hepatocellular carcinoma, nine patients were studied in detail. Each received two courses of a bolus injection of Adriamycin (60 mg/m2), in one of which the Adriamycin was mixed with 10 ml of lipiodol. Analysis of the paired data, and additional 'non-paired' data from a further seven patients, showed that there was no significant difference in the area under the concentration-time curve for Adriamycin or adriamycinol or, in the case of Adriamycin, the terminal half-life. Likewise the fall in haemoglobin concentration, white cell count and platelet count following treatment, and the degree of nausea and vomiting were not significantly different. Comparison with a series of 12 patients receiving intravenous Adriamycin, in the same dose schedule, revealed no difference in terms of pharmacokinetic parameters or toxicity with intraarterial administration of Adriamycin, with or without lipiodol.