Acetaminophen intoxication can cause hepatic, renal, and myocardial necrosis which is often fatal. These lesions develop very rapidly, perhaps during the first pass of the drug through the liver. In case of acute ingestion of an overdose it is therefore essential to employ measures for reducing the absorption of acetaminophen. The effect of activated charcoal on acetaminophen absorption by normal volunteers was determined as a function of the dose of charcoal, the dosage form of acetaminophen, and the charcoal-to-acetaminophen dose ratio. The results indicate that activated charcoal can be an effective antidote for acute acetaminophen intoxication, if administered promptly and in sufficient quantity.