The doctor often says my child has a viral infection. Because viruses are so small and live within the cell, antibiotics do not work against viruses. Thus, with most infections in children, antibiotics are of no help. The child's immune system will get rid of the virus in 5 - 8 days.
Bacteria are larger infectious agents than viruses and live outside the cell.
Therefore, antibiotics can be used effectively against most bacteria. Again, most infections with children are viral but there are some definite bacterial infections. As with all treatments, using antibiotics carries both a risk and a benefit. The benefit is that if there is truly a bacterial infection which is a threat to the child, the antibiotic will help the child get well. There are many risks to antibiotics.