Intraosseous (IO) access in adults via the distal tibia has never been a widely accepted technique. Yet there have been occasional reports of the successful use of this procedure. This study was done to demonstrate the utility of IO infusions in the adult patient, including those patients in cardiac arrest. Twenty-two patients, aged 36 through 84 (mean 65.1 years), who arrived in the emergency department (ED) in cardiac arrest from nonhypovolemic causes and in whom an intravenous line was not established prior to arrival or was found to be inadequate (nonfunctioning or poorly functioning) upon arrival in the ED, had an IO needle (13-gauge Kormed/Jamshidi, Pharmaseal Division, Baxter Healthcare Corp., Valencia, CA) placed above the medial malleolus. The IO needle was then connected to a standard IV tubing, with a pressure bag or pressure device delivering 300 mm Hg to the solution bag. The resultant flow rate through the IV line ranged from 5 to 12 mL/min. The IO needle was placed and flow established in under one minute in all patients. Temporally related pharmacologic effects were observed after the IO administration of sodium bicarbonate, lidocaine, atropine, and vasopressors. This study shows that I.O. access can be quickly and easily obtained in adults in the medial supramalleolar position during cardiac arrest. This method of drug administration appears to hold promise as another useful modality for adults and older children during nontraumatic resuscitations.