Phenytoin is a widely used anticonvulsant drug in the ICU that requires therapeutic drug monitoring. It carries a major risk of dose-related toxicity because of its saturation (zero-order) pharmacokinetic. Hepatic injury with phenytoin is common and varies from almost trivial to massive necrosis and is usually hepatocellular. Here, we report on a 45-year-old woman who was admitted to the ICU with subarachnoid hemorrhage and developed an acute liver injury 16 days after phenytoin injection. Phenytoin was stopped and replaced by oxcarbazepine. Possible drug interactions and risk factors are also discussed.