Oral glucose tolerance test is valuable for diagnosing diabetes. However, the following matters should be noted: 1. Three days before the test, you can eat a normal diet (eating not less than 250-300g of carbohydrates per day) and discontinue insulin therapy. The day before the experiment dinner that is no longer eaten. 2, fasting time of 10-16 hours, 7-9 a.m. to start the test. 3, 8 hours before the test, smoking, drinking alcohol and coffee are prohibited, but you can drink moderate amount of water when your mouth is dry. 4.Avoid abnormal physical activity, mental tension and various stimuli. 5.To avoid nausea and vomiting, glucose can be diluted to 25% oral concentration. 6, such as oral contraceptive drugs, hypoglycemic drugs, sodium salicylate, insulin and certain diuretics, hormones, etc., should be stopped three days before the test.