In March, 2010, a 15-year-old girl presented to our accident and emergency department with altered mental status, nausea, and vomiting. During the previous evening she had been out with friends, and had consumed a white powdery substance together with alcohol. On the day of admission she had become increasingly unwell, with symptoms that could not be attributed to a hangover and presented to us in the afternoon. Upon arrival, our patient was somnolent with a Glasgow Coma Score of 11 she opened her eyes in response to speech, uttered inappropriate words, and localised to pain. Blood pressure was 108/58 mm Hg; pulse rate was 54 beats per min; respiratory rate was 15 breaths per min; and ear-temperature was 36°C. Arterial blood gas analysis and 12-lead electrocardiogram were normal. There was no evidence of external injury, neck stiffness, or localising neurological signs. Her pupils were dilated but reactive to light; there was no papilloedema. The remainder of the physical examination was normal.