Food poisoning, if it is bad enough, can give you chills. They usually accompany a fever in those ill with food poisoning. The fever could be more severe in those who are younger than three months. If it is accompanied by severe diarrhea or the fever stays for more than two or three days, you want to go to the hospital. However, pregnant women should go to the hospital or at least see a doctor if they’re having severe diarrhea.
With any other illness, you should see the doctor in two to three days if the symptoms don’t clear up. If you’re worried before that, go see your doctor. Be warned that diarrhea might continue up to a week after the other symptoms clear.