Multiple-dose charcoal therapy has been shown to increase the excretion of some drugs. This study assesses the effects of this intervention on salicylate excretion in the postabsorptive phase. Ten human volunteers participated in this randomized, controlled, crossover, two-limbed protocol. On two occasions each volunteer ingested 2880 mg of aspirin. During the experimental limb, 25 g of activated charcoal was ingested at 4, 6, 8, and 10 hours after drug ingestion. Pharmacokinetic data were derived from serial serum salicylate concentrations, and urinary salicylate excretion was quantified. Treatment effects were 9% and 18%, respectively. Although both are significant, they are clinically modest, making multiple-dose charcoal therapy of questionable value for acute salicylate poisoning. Controlled data demonstrating the clinical efficacy of this therapy are required to validate it as an intervention for this condition.