Before gastroenteroscopy, it is necessary to take drugs such as polyethylene glycol electrolyte bulk, dimethylsilicone oil emulsion, dacronine hydrochloride gelatin paste and so on as prescribed by the doctor. 1. Polyethylene glycol electrolyte bulk: mainly used for preoperative intestinal cleansing preparations and intestinal cleansing preparations before colonoscopy and other examinations, long-term use of nausea, vomiting and other adverse reactions may occur, allergic to the drug is prohibited. 2. Dimethylsilicone oil emulsion: the drug is suitable for abdominal symptoms caused by gas in the gastrointestinal tract. When performing gastroscopy, the foamy mucus in the stomach is removed, which can improve the clarity of gastroscopy. Long-term use may cause adverse reactions such as diarrhea, and is contraindicated in people who are allergic to the drug. 3. Dacronin Hydrochloride Collodion: It is a local anesthetic, suitable for laryngeal anesthesia during gastroscopy, and at the same time removes the foam in the lumen and makes the field of vision clear. Prolonged use may cause headache and other adverse reactions, and is contraindicated for those who are allergic to dacronin hydrochloride. Before gastroenteroscopy, you should complete the relevant examinations, truthfully inform the doctor of the history of disease, drug allergies, etc., and choose the appropriate drugs under the guidance of the doctor. If there are other discomforts of gastroenteroscopy, you should seek medical treatment in time.