Drinking milk 12 hours before a gastroscopy does not usually affect the results. Gastroscopy, including painless gastroscopy and general gastroscopy, can directly observe lesions in the esophagus, stomach, duodenum, oropharynx and other parts of the body, and is one of the most commonly used tests for checking upper gastrointestinal diseases. You need to keep fasting before gastroscopy, you need to fast for 6~8 hours and 4 hours of water fasting, which will help to empty the food in the stomach and facilitate the doctor to observe the lesions in the stomach more clearly and directly in the process of gastroscopy. Therefore, drinking milk 12 hours before gastroscopy generally does not affect the effect, when the milk has been eliminated from the stomach. Patients who need to undergo gastroscopy should actively cooperate with the doctor’s procedure.