We present a widespread pneumocephalus case as an unreported complication of influenza infection. The patient suffered from headache, mental changes, delirium, unconsciousness and seizures after a massive and clear running nose. Cranial CT showed widespread air collection in the subarachnoid spaces. The patient was hospitalised and treated with a conservative regimen. Pneumocephalus resolved spontaneously and the patient healed completely. Cranial CT from the third week of treatment was nearly normal.