The combination of Tumour Necrosis Factor (TNF) and mitoxantrone was evaluated for potential chemotherapeutic effect against a human ovarian cancer cell line A2774 hetero-transplanted in female nude mice. Both antitumour efficacy (relative survival and reduction of ascites) and toxicity (weight loss and liver toxicity) of TNF alone, mitoxantrone alone or TNF + mitoxantrone were evaluated. A significant difference (P < 0.002) was observed only among animals bearing tumours treated with mitoxantrone (0.012 mg/Kg) + TNF (5 x 10(5) U/Kg) and controls. No cytotoxic effects were observed for this combination. These observations provide a rationale for further evaluation of TNF + mitoxantrone based regimes for the treatment of recurrent ovarian cancer.