Drinking water in between glucose tolerance tests is not recommended and may affect the accuracy of the results. Glucose tolerance test is mainly used to diagnose diabetes, blood is drawn before taking glucose, 30 minutes, 60 minutes, 120 minutes and 180 minutes after taking oral glucose to detect glucose, which can reflect the body’s pancreatic function, and make a certain degree of differentiation between type 1 diabetes mellitus and type 2 diabetes mellitus. Drinking water in the middle of the test may cause the blood glucose to be diluted and thus not reflect the real situation, so it is recommended that patients do not consume water in the middle of the test. In conclusion, it is recommended that patients take into account their own situation and conduct the test under the guidance of the examining doctor.