A prospective pilot trial was performed in 20 patients randomised to receive either (131)I-Lipiodol therapy alone (n=10) or (131)I-Lipiodol combined with a short low-dose cisplatin infusion (n=10), the aim being to evaluate the possible positive influence of a radiosensitiser on toxicity and tumour response. An activity of 1,354-2,128 MBq (mean 1,824 MBq) [36.6-57.5 mCi (mean 49.3 mCi)] (131)I-labelled Lipiodol was administered by selective instillation in the hepatic artery. Cisplatin was given in a dose of 30 mg/m(2) at day -1 and day +6 (day 0: (131)I-Lipiodol). The primary endpoint of this trial was toxicity of therapy; points of secondary interest were tumour response and survival at 6 months. With the use of cisplatin we found a higher percentage of stable or diminished tumour size (90%, vs 40% without). A benefit in group survival at 6 months was not evident. Low-grade stomatitis in one patient and minor changes in peripheral blood count were probably directly related to cisplatin, but its administration is unlikely to be associated with an excess of serious side-effects. The use of low-dose cisplatin infusion as a radiosensitising agent in (131)I-Lipiodol therapy for hepatocellular carcinoma seems safe and may be beneficial for tumour control. Larger patient groups are necessary for confirmation and to establish the future role of (131)I-Lipiodol in hepatocellular carcinoma.