1 The ability of activated charcoal to prevent the absorption of amiodarone was studied in 18 healthy volunteers, divided into three groups of six subjects. 2 All subjects were administered a single dose of 400 mg amiodarone; one group ingested the drug with water only (control) and the second with 25 g of activated charcoal as a water suspension. The subjects in the third group were given 25 g of charcoal immediately after the 1.5 h blood sample. 3 The extent of amiodarone absorption was reduced by about 98% by simultaneously administered charcoal (P less than 0.001); taking charcoal 1.5 h after amiodarone still resulted in a 50% reduction in amiodarone bioavailability (P less than 0.05). 4 These results indicate that activated charcoal should be effective in preventing amiodarone absorption in acute poisoning.