The invention relates to a dressing assembly arrangement and a method for treating a wound of a human or animal body by means of negative pressure. The dressing assembly comprises an absorption body for absorbing wound secretion, wherein the absorption body is designed for inserting into a cavity of the wound. A separation element is also provided, which is arranged between the wound and the absorption body. Further, a cover element, which is designed for substantially airtight covering of the wound with the absorption body, and a connection device, which is arranged for connecting a negative pressure source to the cover element, are provided. According to the invention, the separation element is designed to be larger than the wound to be treated, wherein a protruding edge portion is formed, and the edge portion is applied on a skin region at the edge of the wound.