Endoscopic submucosal dissection (ESD) is a relatively well-established minimally invasive method for the treatment of early cancers and precancerous lesions of the gastrointestinal tract and is generally safe. However, it has some drawbacks, i.e., postoperative complications such as abdominal pain, fever, nausea and vomiting, postoperative eructation, and bleeding and gastrointestinal perforation may result. 1. Abdominal pain: Gas will be injected into the intestines during the operation, if the gas is not completely discharged after the operation, there will be slight abdominal pain. You should rest quietly and avoid hard activities. If the pain is severe, you should report it to your doctor. 2. Fever: There will be mild fever after the operation, and the body temperature is usually below 38℃, and will return to normal in 3~5 days. If the fever lasts for more than 1 week or the temperature keeps rising, the complication of infection should be considered. 3. Nausea and vomiting: it is generally a reaction to anesthesia, which can be relieved after the anesthesia drugs disappear. 4. Postoperative eructation: it may be caused by stimulation of nerve center or diaphragm due to surgery, which can be done by compression of supraorbital nerve, short-term inhalation of carbon dioxide, gastrointestinal decompression, or administration of sedative drugs. 5. Bleeding and perforation of the digestive tract: Postoperative bleeding can be caused by the shedding of blood crusts from the blood vessels of the wound and tearing of the closed wound. In addition, perforation may occur when this procedure is performed to treat submucosal tumors of the GI tract. After endoscopic mucosal resection, if you have any of the above uncomfortable symptoms, consult your doctor and take corresponding treatment according to your doctor’s advice.