To assess signs that might be used in the decision whether or not to admit a patient with minor head injury, the records of 713 female and 1163 male patients were reviewed. Skull radiographs were not obtained routinely; all patients were able to walk and talk when they reached medical contact. Nine patients developed an intracranial complication. The risk of developing such a complication was 16.7 per cent when the patient was agitated, 3.4 per cent in the presence of impaired consciousness and 2.1 per cent when positive neurological signs were observed at the time of examination. Based on the medical history, amnesia for > 5 min and vomiting were associated with a risk of 3.3 and 1.2 per cent respectively; the risk increased considerably in the presence of both. It is recommended that all patients presenting themselves with one or more of the above symptoms or signs, or with alcohol intoxication, after a minor head injury be admitted for observation. If these guidelines had been used, all patients with an intracranial complication would have been detected, and 44.5 per cent of the bed-days used would have been saved.