Usually, gastroscopy requires more than 6 hours of fasting. Gastroscopy is the preferred method of examination for lesions in the upper gastrointestinal tract, allowing direct observation of the true condition of the examined area, and can further clarify the diagnosis by performing pathological biopsy and cytological examination of the suspected lesion. Gastroscopy must be done on an empty stomach, otherwise the presence of food residues will affect the observation of gastric lesions. The general gastrointestinal emptying time is about 4-6 hours, so it is necessary to keep fasting for at least 6 hours. It is generally required to stop eating after 20:00 on the night before the examination, and to continue fasting in the morning of the second day and perform gastroscopy on an empty stomach. However, there are special cases, such as long-term hypertension, which requires oral antihypertensive drugs every morning, and in this case, oral antihypertensive drugs can be taken 4-6 hours before the examination. If you have diabetes, you need to carry a sugar cube with you to avoid the symptoms of hypoglycemia caused by long fasting time. The gastrointestinal tract needs to be carefully prepared before gastroscopy in order to perform gastroscopy efficiently and accurately and to clarify the lesion.