More than half a million U.S. children every year have bad reactions or side effects from widely used medicines. The reactions can require medical treatment and sometimes hospitalization.
Children younger than age 5 are most commonly affected. Penicillin and other prescription antibiotics are among drugs causing the most problems, including rashes, stomachaches and diarrhea.
The data is based on national statistics about patients' visits to clinics and emergency rooms between 1995 and 2005. The number of children treated for bad drug reactions each year averaged almost 586,000.