BACKGROUND: Oxaliplatin is a new generation platinum derivative, and has become a part of the medical treatment for solid cancer. It induces two distinct forms of neurotoxicity. An acute reversible syndrome shortly after the infusion is attributed to the transient hyperexcitability of the peripheral nerves and a dose-limiting chronic sensory neuropathy results from the cumulative toxic doses. This study was undertaken to evaluate the incidence and pattern of the clinical and electrophysiological abnormalities with the transient hyperexcitability syndrome. METHODS: 22 patients received Oxaliplatin as part of the FOLFOX schedule for anticancer therapy. Clinical symptoms were assessed by a standardized questionnaire. Electrophysiological investigations included sensory and motor nerve conduction studies of the median nerve and an electromyogram of the thenar. Investigations were performed 24 hours following Oxaliplatin and 13 days thereafter. RESULTS: 72% of the patients reported symptoms after Oxaliplatin, predominantly cold-induced painful parethesias of the hands, legs and throat and muscle cramps in the respective regions. They were more frequent in the second or further FOLFOX cycles and more disabling with higher cumulative doses. Myokymia and muscle twitching was seen in 47%. Thirteen days thereafter the above-mentioned symptoms had resolved completely. Nerve conduction studies did not differ at both times. After Oxaliplatin, single motor nerve stimuli induced repetitive muscle action potentials in 70% of the patients and the EMG disclosed neuromyotonic discharges in 85%. The more severe the clinical complaints, the more prominent were the electrophysiological abnormalities. However, even in 5 out of 6 asymptomatic patients electrophysiological abnormalities were evident. 13 days thereafter, except one patient, all abnormalities had subsided. CONCLUSION: This study confirms the high incidence of acute but reversible adverse events with Oxaliplatin therapy and highlights the nerve conduction studies and the EMG as valuable tools to disclose this hyperexcitablity syndrome of the peripheral nerve.