Fasting physical examination is recommended not to eat food or drink water. 6-8 hours before the physical examination requires fasting water, this is because certain examination items will have certain effects after drinking water, such as blood testing biochemical indicators, such as liver function, kidney function, blood sugar, blood lipids, ions, etc., after drinking water will cause a certain dilution of blood, so try not to drink water. There are also some examination items, such as liver, gallbladder and spleen ultrasound, if you drink water, it will cause the gallbladder to contract, so you can’t see the gallbladder at this time, so you can’t drink water either. You should not eat anything during gastroscopy, including drinking water. If you don’t have any of the above items, you can drink a small amount of water, no more than 200ml of water.