Chances are your well-baby visits won't be the only time you're talking to the doctor. The onset of a cold sends parents running for the pediatrician's number anywhere from one to six times—and sometimes more—during a baby's first year of life. Remember, infants are born with immature immune systems, so it's easy for them to catch bugs.

If your baby is younger than six months, it's especially important to check in with a health care professional whenever baby seems sick, particularly if your child is running a fever. Certain illnesses, such as the lung infection called respiratory syncytial virus (RSV), barely affect adults but can require hospitalization for an infant. If your baby seems lethargic and is unresponsive; is running a fever of over 100 degrees if younger than three months; or if your baby is showing signs of dehydration (including fewer tears when crying and fewer than four wet diapers a day), call the doctor and ask for an appointment. Don't treat a baby younger than six months at home with any medications—they're likely too powerful for baby's little body. Your pediatrician will be your best guide for how to make an infant feel better.

Once your child has cleared the first six months, baby's just as likely to get sick. But because your little one's immune system is toughening up, illnesses are not as worrisome. Your pediatrician can help you manage baby's symptoms by recommending nasal drops to clear up nose ailments, acetaminophen or ibuprofen to temporarily ease aches and fever, and perhaps a cool-mist humidifier to keep sinuses open. Be sure to offer lots of breast milk and formula in the meantime, so there's no chance of dehydration.

It's actually pretty rare for a baby under a year to get a full-blown attack of the flu. Both colds and flus are caused by viruses, but the flu can include high fevers, muscle aches, fatigue, and sometimes vomiting and diarrhea. A cold is limited to slight fevers, coughs, sneezes, a decreased appetite, and stuffiness, and is more common.

After baby's first birthday you can be more aggressive with over-the-counter medication to fight colds and flus, provided your pediatrician gives an okay. (Never give baby any medicine without clearing it with the doctor first.) Beware that antihistamines are likely to make baby look lethargic, and decongestants tend to raise heart rates and make babies agitated. Cough suppressants have no significant side effects and can be helpful if your child is having trouble sleeping through a hacking cough. None of these medications can 'cure' a viral infection; a cold or flu simply has to run its course. And in that case, lots of rest and snuggles from mom and dad are the best cures.