What's normal: Two or three episodes a year is average. Babies may spit up once a day.
What's not: Repeated vomiting on any given day.
Why your child may be vulnerable: True vomiting -- usually a reaction to infection, food poisoning, or stress -- is different from a baby's everyday spit-up, Dr. Fisher says. The gastrointestinal system of some babies takes extra time to mature, and they'll experience wet burps or gastroesophageal reflux. "This is normal," she notes.
But if your baby or toddler vomits fiercely after each feeding, she may have a condition known as pyloric stenosis, a thickening of the valve between the tummy and intestines that keeps the stomach contents from emptying. Some babies and preschoolers gag easily while eating or having their teeth brushed, causing them to vomit.
Other preschoolers (and elementary school kids) could have cyclic vomiting syndrome. This condition involves intense vomiting for several hours or even days, followed by weeks or months of peace.
Advice for parents: If your pediatrician can't diagnose the cause of your child's vomiting, consider consulting a pediatric gastroenterologist.