For application of active substances to a wound surface a porous padding (12) is provided upon the wound (10), which is sealingly covered over with a foil (14). A fluid active substance is introduced into the padding (12) via a supply line (22) and is then suctioned out of the padding (12) via a removal line (26). Closure mechanisms (32, 34) control the introduction of the active substance and the suctioning off of the active substance in the manner, that the active substance after being introduced remains for a predetermined dwell time in the padding (12), before it is suctioned off. After the suctioning off the vacuum in the padding (12) is maintained for a certain time period, before renewed introduction of the active substance. The opening of the closure mechanisms (32, 34) are temporally controlled to occur slowly.