Fat liquefaction usually refers to the rupture, decomposition, and spillage of a large number of fat cells around the incision after surgery, resulting in the formation of more ooze around the incision, which can easily cause infection or poor healing of the surgical incision. It is usually seen in obese, old and frail patients or diabetic patients, and often occurs about 1 week after surgery. Most of them have no redness, swelling and pressure pain around the incision, and are not accompanied by systemic symptoms, but can produce serious systemic symptoms when combined with incision infection or sepsis. 1, the causes of fat liquefaction 1, obesity, old age and weakness or diabetes and other basic diseases affect the healing of the incision; 2, subcutaneous fat-rich areas using electric knife surgery, high temperature caused by the denaturation of subcutaneous adipose tissue, postoperative sterile necrosis, postoperative incision dressing a large number of yellow ooze. 3. Long operation time and long and heavy tissue pulling also easily cause fat liquefaction; Second, what should I do when fat liquefaction occurs? 1.Usually, timely dressing change and avoiding infection are the main concerns; 2.If there is more exudate and possible combined infection, thorough debridement is needed; 3.Antibiotics are often needed to prevent infection in case of fat liquefaction; negative pressure suction technique (VSD) can be used for patients with more exudate and frequent dressing change of the incision.