Glucose tolerance generally refers to the glucose tolerance test, if you drink a small amount of water before doing the glucose tolerance test does not need special treatment, if a large amount of water may cause inaccurate blood glucose test results, it is recommended to change the time and then perform the glucose tolerance test check. Try not to drink any water before the glucose tolerance test. If you are really thirsty, you can drink a small amount of plain water or purified water, but not drinks. Drinking a small amount of plain water will not affect the glucose tolerance test result, so this is usually fine and does not require special treatment. If you drink a lot of water before the test, it may have a certain effect on the test results, so it is not recommended to take the glucose tolerance test on the next day, and you need to change the test time and strictly follow the dietary precautions before taking the test. Patients who need to do glucose tolerance test should be under the guidance of the doctor.