As with any illness, judgment is needed to determine if and when to seek medical care. If symptoms are severe (vomiting, diarrhea, fever or cramps) or the victim is very young, elderly, pregnant or already ill, call a doctor or go to the hospital immediately. It's not always easy to tell if the problem is the result of flu or food poisoning. You or your physician should report serious cases of foodborne illness to the local health department. If you think the food involved came from a restaurant or commercial outlet, you may be asked to keep the food refrigerated so officials can examine it later.