Antibiotics are another class of medication altogether. They're used to fight bacterial infections, your pediatrician can tell a viral illness from a bacterial one. Most ear infections, for example, are bacterial infections that require antibiotics to get rid of them. Strep throat requires antibiotics and is different from a viral cough; a laboratory should diagnose your child with strep throat before you start giving antibiotics. The same holds true for severe sinus infections, which are different from runny noses.

In order for antibiotics to work, you have to be sure to give baby the entire prescription even if you think the condition has cleared up, keep the medication refrigerated if it needs to be, and call your pediatrician if you have questions. For example, don't hesitate to call if your baby is throwing up or spitting out medicine. There is some concern among pediatricians that children who receive too many antibiotics may become immune to them later in life—so again, don't give them out for every little ailment.

Ear infections (called 'acute otitis media') are extremely common—two-thirds of all children have one before their second birthday. When baby has a cold or flu, some fluid is likely to back up in the middle ear. This triggers the bacterial infection. Babies with ear infections may show it by crying more during feedings (because the sucking is painful), suffering from insomnia (since lying down increases the pressure from the fluid), and running a fever.

A pediatrician can diagnose an ear infection by checking baby's ears with an otoscope. She may prescribe ear drops to numb the pain, as well as antibiotics (usually in liquid form for babies). On occasion the first antibiotic won't work, and you'll have to try a second. Also, there's a chance that if your baby seems particularly prone to ear infections, your pediatrician will prescribe preventive antibiotics.

But don't let the common cold worry you too much—the fact is, fighting off colds and infections is one way baby builds immunity. It's hard to imagine an illness being good for a baby, and certainly it's nothing you wish on your child, but when an infant's body fights these bugs—with help from medication prescribed by a pediatrician—it does grow stronger. The big exceptions, of course, are the serious illnesses that vaccinations protect against. You don't want your baby to ever have to fight something as serious as whooping cough or even chicken pox, for instance, so keep up with the shot schedule and baby will stay strong.