The precautions before doing glucose tolerance mainly include fasting for 8 to 10 hours the night before the test, stopping diuretics, birth control pills and other medications for 3 to 7 days before the test, banning the use of insulin on the day of the test, and avoiding fatigue and mental stress before the test. Glucose tolerance, i.e. glucose tolerance test (OGTT), is a common test in which the examinee fasts for 8 to 10 hours the night before, and then 75 grams of glucose is added to 250 to 300 ml of water early in the morning of the next day and drunk within 5 minutes to measure the fasting glucose and the glucose after 2 hours. The examinee should have a normal and reasonable diet 3 days before the glucose tolerance test, and should not deliberately reduce the consumption of carbohydrates, not to mention eating more food with high sugar content. Stop using diuretics, birth control pills and other drugs 3 to 7 days before the test, and prohibit the use of insulin on the day of the test. Maintain normal daily activities before the test, avoid excessive exertion, and keep emotional stability and relaxed mood. Glucose tolerance test should be conducted under the guidance of doctor.