Ciprofloxacin or doxycycline is recommended for antimicrobial prophylaxis and treatment of adults and children with Bacillus anthracis infection associated with the recent bioterrorist attacks in the United States. Amoxicillin is an option for antimicrobial prophylaxis for children and pregnant women and to complete treatment of cutaneous disease when B. anthracis is susceptible to penicillin, as is the case in the recent attacks. Use of ciprofloxacin or doxycycline might be associated with adverse effects in children, and liquid formulations of these drugs are not widely available. This notice provides further information about prophylaxis and treatment of children and breastfeeding mothers, including the use of amoxicillin.