The causes of increased drainage after surgery are closely related to the type of surgery and the site of surgery. Common drainage includes drainage of thoracic and abdominal fluid, drainage from the skin surgery area, biliary drainage and anastomotic drainage, etc. The specific causes include hypoproteinemia, incomplete removal of the lesion area, large scope of injury, infection and anastomotic fistula. 1. Thoracic and abdominal fluid drainage: in the process of drainage, if the amount of drainage fluid is relatively large, it is very likely that it is caused by the continuous leakage of fluid, which is closely related to hypoproteinemia, the lesion area is not completely removed, and the deviation of the physical condition will be manifested accordingly. 2. Drainage from skin surgery area: after trauma, burn or infection, it is necessary to drain the skin surgery area, and the amount of drainage fluid increases, which is mainly closely related to the large scope of injury and local infection, and will cause continuous leakage of fluid. 3. Biliary drainage: the main purpose is to relieve jaundice, the surrounding obvious infection will lead to an increase in the amount of fluid, causing increased drainage. 4. Anastomotic drainage: mainly refers to gastrointestinal surgery, during surgery, if there is a continuous increase in drainage fluid, or even drainage of digestive fluids, it is very likely that it is caused by poor recovery, and may result in the formation of anastomotic fistula. Once there is a significant increase in drainage fluid, continued not to improve, you need to communicate with your doctor in a timely manner, under the guidance of the clinician for standardized treatment.