Trimelamol is an analogue of hexamethymelamine which exhibited activity against refractory ovarian cancer in phase I clinical trial. The dose limiting toxicity was leukopenia. In a phase II study, 42 patients with recurrent, or platinum-complex resistant, advanced ovarian cancer were treated using the dose schedule 800 mg m-2 i.v. daily for 3 days. There were one complete, three partial and five minor responses, objective response rate: 9.5%. The main toxicity observed was nausea and vomiting, myelosuppression was minor. The role of Trimelamol in the treatment of ovarian cancer remains to be defined, but its activity is limited in refractory disease.