A total of 15 patients with relapsed high-grade glioma were treated with carboplatin (400 mg/m2) or iproplatin (300 mg/m2). All had received previous radiotherapy, and 12 had previously undergone chemotherapy. One of the ten patients treated with carboplatin and one of the five treated with iproplatin achieved a partial remission as determined by repeat computerised tomographic (CT) scan. Myelosuppression was considerable, as three patients developed grade IV neurotoxicity, which was fatal in one case. Although carboplatin and iproplatin showed activity against malignant glioma, the study was closed because of unacceptable toxicity.