To evaluate the neurotoxicity of paclitaxel/cisplatin chemotherapy, we studied neurological and electrophysiological functions in 14 patients who had been treated with 1-7 courses of paclitaxel/cisplatin. The cumulative paclitaxel and cisplatin doses ranged from 175 to 1225 mg/m2 and 100-700 mg/m2, respectively. Neurological examinations as well as motor nerve conduction studies of the peroneal nerve were performed and summarised by means of a peripheral neuropathy score. Neurotoxicity with onset usually after the second treatment cycle occurred in 13 patients. 12 patients complained about sensory symptoms, 13 patients had impaired vibration sense and 8 patients developed additional muscle weakness, predominantly of the legs. Dysfunction of peroneal motor nerve conduction occurred in 13 patients. Reduction of amplitudes as well as slowing of conduction velocities were seen in 13 patients and prolonged distal latencies in 10 patients. The peripheral neuropathy score was elevated in 13 patients. Neurological symptoms, impairment of both vibration sense and tendon reflexes, and the peripheral neuropathy score increased with the cumulative doses of paclitaxel/cisplatin. Serial analysis among selected patients also revealed an increase in neurotoxicity with increasing cumulative drug doses. These data indicate the development of neurotoxicity in most patients treated with paclitaxel/cisplatin and also suggest that early signs of neurotoxicity can be detected by clinical examination with emphasis on symptoms as well as vibration sense and can be well documented by electrophysiological investigations.