The drainage tube is used for drainage, which is the pipeline used for drainage. When there is a lesion in the body, drain the fluid out of the body. For example, if there is pus in the abdominal cavity, a drainage tube needs to be used to drain the pus, or if there is something else inside, such as bleeding, a drainage tube can also be used to drain the pus. Drainage tubes are often used during surgery, such as appendicitis in the abdominal cavity, perforation of the appendix, or local abscess. Place the drainage tube into the pus cavity to allow all the pus inside to flow out and gradually dissipate the inflammation. After trauma or rupture of an ectopic pregnancy, a large amount of intraperitoneal bleeding can occur, and a drainage tube can be placed to draw the blood out. In addition, the drainage tube can also be used for observation. Placing the drainage tube in the abdominal cavity or chest cavity can determine whether there is any further bleeding on the surface, because once there is further bleeding, the drainage tube will drain the blood out.