An 11-mo-old child with primary hyperoxaluria was scheduled for a nephroureteromia procedure. Anesthesia was induced and maintained with sevoflurane. Two days after the operation, a hepatomegaly was diagnosed, and a considerable increase in liver enzymes was observed. These pathologic findings disappeared without treatment within 7 days. In a subsequent operation 2 wk later, general anesthesia was performed (sevoflurane was avoided). After the second operation, no pathologic findings could be detected. Nothing in this patient's disease or the conduct of the anesthesia suggested a cause for the injury other than an idiosyncratic response to sevoflurane.