A glucose tolerance test usually requires fasting for about 8 to 10 hours. During this period, it is recommended to drink a small amount of water, but preferably less than 100 ml. When drinking water, it is best to choose plain water, as plain water does not contain energy, and it is recommended not to drink beverages, and not to consume food after 10:00 p.m. at night. For patients who undergo glucose tolerance test, in addition to the requirement of fasting, it is also necessary to pay attention to 3-7 days before the test to stop using drugs that may affect blood glucose, from the day before the test and during the test do not drink stimulating drinks and do not smoke and drink alcohol, and before the test to avoid strenuous physical activity. In case of acute myocardial infarction, surgery and other stressful conditions, we should wait until the condition has fully recovered before doing the test. If there are “three more and one less” (more drinking, more urination, more food, weight loss) and other uncomfortable symptoms, you need to consult a doctor in time, whether it is necessary to do the glucose tolerance test, under the guidance of the doctor to clarify the cause of further treatment or therapy.