Many parents may also wonder when it is safe for their child to go back to school after recovering from their illness.
"The answer to that one is a little bit trickier," says ABC News medical editor Dr. Tim Johnson. "In general, nobody would recommend that a child goes back to school unless they have been fever-free for 24 hours, and some would even say 48 hours."
Jana says a full day of fever-free downtime is probably sufficient to safeguard the child's health, as well as that of his or her peers.
"It is fairly standard that children are required to be fever-free for 24 hours before returning, which I repeatedly explain is a useful method of limiting the spread of infection during the febrile period when children are thought to be most contagious," she says.
Johnston agrees. "When the fever is gone for 24 hours, the contagiousness is greatly diminished."
The 24-hour rule may prove to be more than sufficient for vomiting, Johnston says.
"Vomiting is a temporary nuisance most of the time," he says. "So if the child feels OK and has not vomited since midnight, I will allow them to go [the next morning]."
In most cases, however, the decision of whether or not to send a sick kid to school will not be clear-cut. In these cases, parents must ask themselves certain questions to help them decide.
Will the illness prevent the child's participation in normal school activities? Also, will the child's illness place an unusual burden on the staff?
A third and very important question to consider is whether or not the illness that the child has poses a risk to other children and adults.
Parents must also keep in mind that those complaints of abdominal pain could be from a food-borne illness -- or they could just be due to anxiety over the prospect of going to school.
But in these situations, it may be better to err on the side of caution.
"Parents have to be willing to trust their instincts," Johnson says. "Even when their child is not having any objective signs of illness, if they think that the child is different from how they normally are, they need to trust their instincts and keep the child at home until they figure out what's wrong.
"Just because a kid does not have a fever does not necessarily mean that they are well."
Johnson says some signs that you should keep your kid at home are a high fever, significant coughing, an unexplained rash or pink eye, and uncontrolled vomiting or diarrhea.
Parents should also be aware of symptoms that suggest the child should be brought to a doctor. If the child cannot touch his chin to his chest, it could be a sign of meningitis, a serious infection that warrants immediate medical attention.