A person should never drink tap water in China. Bottled water is readily available. A person should always check to see that the seal on the bottled water is unbroken. At times, an institution will make a water dispenser available in the foreign teacher’s apartment.
Food should be thoroughly cooked. Meats should be cooked through. Be aware that sometimes food purchased on the street, such as roasted meat on a stick, might not be thoroughly cooked. If this is the case and it is eaten, the person will often experience bouts of diarrhea or upset stomach. It is wise to carry chewable Pepto Bismol or some other remedy. The Chinese will often eat a whole clove of raw garlic prior to eating out where they are unsure of the food quality.
If you feel you have food poisoning, you will need to visit a doctor/clinic/hospital for treatment. Inform your host institution and they will help you.
Any fever, diarrhea, or loss of weight over a long period of time needs to be attended to by a physician.