An apparatus for cleansing and promoting tissue growth in wounds, in which irrigant fluid optionally containing cell nutrients and/or other physiologically active material from a reservoir connected to a conformable wound dressing and wound exudate from the dressing are recirculated by a device for moving fluid through a flow path which passes through the dressing, a biodegradable scaffold in contact with the wound bed and a means for fluid cleansing and back to the dressing. The apparatus has means for supplying thermal energy to the fluid in the wound. The cleansing means (which may be a single-phase, e.g. micro-filtration, system or a two-phase, e.g. dialytic system) removes materials deleterious to wound healing, and the cleansed fluid, still containing materials that are beneficial in promoting wound healing, is returned to the wound bed. The dressing and a method of treatment using the apparatus.