Activated charcoal (AC) is most effective when administered soon after the ingestion of certain substances. Delays are recognized to occur at times in the administration of AC after arrival of poisoned patients in the emergency department (ED). In addition, it has been recognized that these delays may be avoided if AC administration is begun in selected patients by paramedics while en route to the ED. We present a pilot study evaluating the administration of AC to poisoned patients in the ambulance prior to arrival in the ED. We performed a retrospective review of Emergency Medical System (EMS) run sheets and ED records of poisoned patients during a 6-month period from two area hospitals. Cases were identified that met criteria for the prehospital administration of AC. Cases were divided into two groups: those who received prehospital AC, and those who did not. Groups were compared for ambulance transport time, time from first paramedic contact to AC administration, and whether AC was tolerated by the patient. A total of 14 patients received prehospital AC (group 1). This group was compared to 22 cases that would have qualified under County protocol to receive prehospital AC, but for whatever reason did not (group 2). Group 2 patients all received AC after arriving in the ED. Average ambulance transport times did not statistically differ among groups. The average time from first encounter with paramedics to administration of AC was 5.0 minutes when AC administration was given in the ambulance as compared to 51.4 minutes when delayed until arrival in the ED. Tolerance was similar among the groups. The time to initiate AC administration may be significantly shortened when begun by prehospital personnel. All EMS should consider including AC in protocols addressing the prehospital management of certain poisoned patients.