We reviewed information about the safety and plasma pharmacokinetic data for amoxicillin, specifically related to its potential use for postexposure inhalational anthrax. Amoxicillin (45 mg/kg/d) given orally in 3 divided doses to pediatric patients <40 kg should yield an adequate time above the MIC for susceptible Bacillus anthracis (< or =0.5 microg/mL) over most of the dosing interval (75-100%). Doses <45 mg/kg/d and dosing intervals longer than 8 hours should not be used for postexposure inhalational anthrax.