The glucose tolerance test is usually done by dissolving 75 grams of anhydrous glucose powder in 250-300 ml of water and mixing it, and drinking it within 5 minutes, so you need to drink 75 grams of glucose for the glucose tolerance test. Fasting for at least 8 hours before the glucose tolerance test, try to avoid eating and drinking. The next day on an empty stomach, blood will first be drawn to check the fasting plasma glucose level, and thereafter, after drinking the mixed glucose water, remembering the time of the first sip of sugar water, blood will be drawn after 0.5 hours, 1 hour, 2 hours, and 3 hours respectively. It is recommended that patients who need to do glucose tolerance test should go to regular hospitals and under the guidance of doctors, so as not to affect the accuracy of the test results.