A cold or the flu will affect a baby more than it will an older child -- that's because babies' immune systems aren't used to fighting off infections. But be prepared: babies can get anywhere from 6 to 10 bouts with bugs in their first year, so make sure you pay extra attention to her symptoms.

Remember to call your pediatrician if:

• Your baby shows any signs of illness if she's less than 3 months old

• Your baby has a 100.4ºF fever and is 3 months or younger; has a 101.1ºF degree fever and is 3 to 6 months, or your baby has a 103ºF degree fever and is over 6 months

• Your baby has a persistent cough or nasal mucus

• Your baby's lips or nails turn blue

• Your baby has breathing difficulties

• Your baby is excessively fatigued or cranky

Keep your baby's nasal passages clear by suctioning out mucus with a rubber bulb syringe, sitting your baby upright in your lap with a hot showering running, or putting a steam vaporizer or cool-mist humidifier in her nursery.

If your baby is vomiting, make sure to keep up fluid intake by offering short but frequent feedings of breast milk or formula, or half an ounce Pedialyte every 10 to 15 minutes. If your baby has a mild fever but otherwise is eating, drinking and playing, monitor his temperature for 24 hours. The AAP recommends notifying your pediatrician if:

• The vomiting continues beyond 24 hours, or if it is high in volume and frequency (meaning she's persistently throwing up everything she's consumed)
• There is blood or bile in the vomit
• Your baby cannot keep any amount of food or liquid down
• Your baby appears lethargic or dehydrated, marked by decreased urination, dry mouth, absent tears, and sunken eyes or fontanelle (the "soft spot" on an infant's skull)
• A high fever accompanies vomiting. High fevers include:
  • 100.4ºF or higher in 3 month-old or younger
  • 101ºF in 3 to 6 month olds
  • 103ºF or higher in babies 6 months and up

If your baby has diarrhea, make sure to keep him hydrated with breast milk, formula or a rehydrating drink. Offer smaller portions of bland foods. Call you pediatrician if:

• Your baby is 3 months or younger
• The diarrhea continues for more than a 24 hours
• Your baby shows signs of dehydration (this includes decreased urination, sunken eyes or soft spot, decreased energy and absent tears)
• There is blood in the diarrhea
• A high fever accompanies diarrhea. High fevers include:
  • 100.4ºF or higher in younger than 3-month old
  • 101.1ºF in 3 to 6 month olds
  • 103ºF or higher in babies 6 months and up

Once your baby is 6 months old, you can have him vaccinated against the seasonal flu as a preventative method. To help prevent illness in your baby, be sure to boost his immune systems (link to immune system pages) by feeding him fruit and veggie-packed baby foods, and making sure your baby gets the recommended 14 hours of sleep every day.