The length of the gastric tube inserted into the stomach is usually 45 to 55 centimeters from the incisors in adults, and usually cannot be inserted too deeply. Gastric tube is mainly used for gastric lavage, continuous gastrointestinal decompression and drainage, prevention and treatment of abdominal pain caused by certain diseases and hemostasis of the digestive tract, which is very helpful for some patients with gastrointestinal obstruction and those who cannot eat. Gastric tubes are usually inserted into adults at a length of 45 to 55 centimeters, and are usually not too deep or too shallow. If the gastric tube is inserted too deep, it may irritate the gastric mucosa, easily cause nausea and other uncomfortable symptoms, or insert the gastric tube into the duodenum and not achieve the desired effect; if the gastric tube is inserted too shallow, it may affect the performance of the gastric tube, resulting in the gastric tube can not be pumped gastric fluid and other phenomena, and some patients may also vomit a lot. Patients need to be guided by a doctor and should not use it without authorization to avoid discomfort.