Drinking water before the physical examination can generally wait a few hours before the physical examination, water excretion is relatively fast, usually about 4 hours on. Many people drink water before the physical examination this situation will affect the blood routine, urine routine and other test results, if the morning of the physical examination drink about 200ml of water, from home to the hospital physical examination office and then to the time you are used to take blood, you drink water has long been absorbed, and has penetrated into the tissue involved in metabolism, and this will not have any effect on the blood indicators. If the examination of the gastrointestinal tract, such as barium meal, gastroscopy, etc., a small amount of water may affect the field of view of the examination, resulting in inaccurate test results or can not be examined. Therefore, do not drink water before the examination, and after drinking water, wait for a period of time according to the amount of water to drink before conducting the examination.