Stomach bug in children is common, but a condition that most parents dread, as it can mean days of nonstop vomiting and diarrhea. While usually the only course of treatment is to stay hydrated and rest, if your child has a fever of 102 F (38.9 C) or higher, is experiencing a lot of discomfort or pain, is lethargic or very irritable, has bloody diarrhea or seems dehydrated, you should consult a pediatrician immediately.