The purpose of liquid paraffin when inserting a gastric tube is to lubricate the tube and make it easier to insert. Gastric tube is a commonly used treatment in clinic, the main purpose is to observe the character of drainage fluid and play the role of gastrointestinal decompression, which can be applied to intestinal obstruction, acute pancreatitis and other patients. In the process of gastric tube insertion, liquid paraffin is needed to lubricate the gastric tube to make it easier to be inserted into the body. The procedure of gastric tube insertion is as follows: firstly, take out the gastric tube and measure the length; then smear the gastric tube with paraffin oil; then insert the gastric tube slowly through the nostril, and when it arrives at the pharynx, ask the patient to do swallowing, and then push the gastric tube again; make sure that the gastric tube enters into the gastric cavity successfully, and then fix the gastric tube; then connect the end of the gastric tube to the negative-pressure suction device, and then the insertion of the gastric tube will be completed.