Parents cannot resist asking me if their child would benefit from an antibiotic, so let me prescribe some advice about when to use antibiotics and when not to. While antibiotics are designed to treat bacterial germs, the majority of childhood illnesses are due to viral germs, and viral germs do not respond to antibiotics. So, if you use antibiotics when you are not sure whether a child has a bacterial or viral illness, this can lead to the development of bacteria that are resistant to antibiotics. In fact, there are already some bacteria that are resistant to some of the most powerful antibiotics. This is why the American Academy of Pediatrics no longer recommends antibiotics for immediate treatment of ear infections since most of these are viral. But if your child has persistent ear pain, then bacteria are likely to be the culprits, and your pediatrician may recommend antibiotics. So what do I recommend? Do not insist on an antibiotic every time your child is ill. Colds, sore throats, stomach aches, and flu symptoms are usually due to viruses and are not immediate reasons to ask for an antibiotic. If you are concerned about your sick child, schedule a visit with your pediatrician rather than just calling the office and asking for an antibiotic. Hold off on antibiotics if it appears that the cause is viral but ask your pediatrician how to make your child more comfortable. If your pediatrician does prescribe an antibiotic, use it as prescribed and only for as long as prescribed. If you have anything left at the end of the treatment period, throw it out; do not save it for use another time. Hopefully, with tips like this, parents will resist the temptation to ask for antibiotics at the first sign of illness. Lewis First, M.D., is chief of Pediatrics at Vermont Childrens Hospital at Fletcher Allen Health Care and chair of the Department of Pediatrics at the University of Vermont College of Medicine. You can also catch First with Kids weekly on WOKO 98.9 FM and WCAX-TV Channel 3. Visit the First with Kids archives at www.vermontchildrens.org.