A 56-year-old female with symptomatic epilepsy was admitted to our hospital because of acute renal failure(ARF) and liver dysfunction(LD) after receiving CBZ for two months. She had suffered a drug eruption caused by phenobarbital and valproate six months previously. Renal and liver biopsies presented acute interstitial nephritis and active chronic hepatitis, respectively. Drug-induced lymphocyte stimulating test showed CBZ positivity. Steroid therapy resulted in recovery from ARF and LD. CBZ sometimes causes ARF or LD, but rarely induces both simultaneously, especially in adults. Pathological evidence of two lesions other than from autopsy seems to be the first step in this case. Cross reaction with other antiepileptic agents was also of interest, suggesting that one member of the cytochrome P450 subfamily, CYP3A, participated in the mechanism.