A 16 year old male who ingested an estimated 6-8 grams of caffeine is described. Caffeine is commonly thought to be harmless, but its wide availability has promoted abuse. This patient manifested many of the adverse effects seen in acute caffeine ingestion including hypokalemia, elevated blood glucose, tachycardia, bigeminy and agitation. Respiratory alkalosis and chest pain, which have not been previously reported to our knowledge in caffeine overdose, were also noted in this patient. Three serum caffeine levels were analyzed and an abnormally long elimination half-life of approximately 16 hours was calculated from the results.