Treatment of phenobarbital poisoning with multiple dose activated charcoal in an infant. A 28-day-old infant developed lethargy, hypotonia, and hypothermia following a phenobarbital overdose secondary to a pharmacist's error. He was treated with multiple dose activated charcoal (MDAC) and alkalinization of the urine, which resulted in prompt recovery with rapid elimination of the drug (t1/2-11.2 hours, expected 45 to 118 hours). The use of MDAC in this newborn was safe and effective. We suggest that age should not pose a barrier to the use of MDAC, when indicated. 