Eight human ovarian cancer lines grown in nude mice were used to compare the activity of doxorubicin, epirubicin, mitoxantrone and menogaril. The tumour lines were different in histological subtype, tumour doubling time and sensitivity to doxorubicin. The compounds were administered intravenously at the maximum tolerated dose twice with one week in between when tumours measured 50-150 mm3. Growth inhibition greater than 50% was obtained for doxorubicin in 8/8, for epirubicin in 4/8, for mitoxantrone in 5/8 and for menogaril in 2/8 tumour lines. In MRI-H-207, doxorubicin was the only drug able to induce complete remission. Compared with doxorubicin, mitoxantrone and menogaril were given in proportionally higher doses than those administered to patients, but did not result in superior antitumour activity.