Extra large dressing change is a clinical method of dressing change for complex wounds, and the general criteria for extra large dressing change are mainly the following: First, the patient’s wound length is long, or the infection is heavy and the area of infection is large. Clinically, patients with intestinal obstruction perform traditional dissection, the surgical incision exceeds twenty centimeters, or patients with burns have a burn area of more than two percent of the body surface, in which case the dressing change takes longer and often requires a large number of wound dressings belong to the criteria for extra large dressing changes. Second, the patient’s wound is more complex and has higher requirements for the doctor, such as a huge pressure sore in the sacrococcygeal area, and the change of medicine requires the debridement of local necrotic tissue, and the change of medicine usually takes about one hour. Only by removing necrotic tissue and filling with iodoform gauze, growth factors, alginate and other excipients, the wound can grow faster, which meets the criteria for extra large dressing changes.