A wound healing system comprising: means for generating an electrical signal; an array of electrodes incorporated in a device for applying said electrical signal to a wound; means for determining the state of the wound; means (24, 26, 36) for creating at least two composite electrodes (14a-14l), each composite electrode being created from at least one of said electrodes in the array and acting as a single electrode, the system being arranged to cause a respective one or more electrodes of the array to form the respective two composite electrodes (14a-14l) depending on desired shape, size and/or location of the respective composite electrodes (14a-14l), the size, the shape or location of each composite electrode being determined by which electrode or electrodes of the array, makes up said composite electrode; and means for causing said electrical signal to be applied to said wound via said at least two composite electrodes (14a-14l), one composite electrode being designated as an anode and the other being designated as a cathode, wherein said means for creating (24, 26, 36) are arranged to determine which electrode or electrodes of the array make up said at least two composite electrodes depending on the determined state of the wound and the wound healing system includes means for selecting said respective one or more electrodes of the array for forming the respective two composite electrodes (14a-14l) based on information concerning the state of the wound, the size, shape and/or location of said at least two composite electrodes (14a-14l) being determined respectively by the size, shape and /or location of the wound with respect to the array, the composition of said at least two composite electrodes being adjustable in response to changes in the determined state of the wound. means for generating an electrical signal; an array of electrodes incorporated in a device for applying said electrical signal to a wound; means for determining the state of the wound; means (24, 26, 36) for creating at least two composite electrodes (14a-14l), each composite electrode being created from at least one of said electrodes in the array and acting as a single electrode, the system being arranged to cause a respective one or more electrodes of the array to form the respective two composite electrodes (14a-14l) depending on desired shape, size and/or location of the respective composite electrodes (14a-14l), the size, the shape or location of each composite electrode being determined by which electrode or electrodes of the array, makes up said composite electrode; and means for causing said electrical signal to be applied to said wound via said at least two composite electrodes (14a-14l), one composite electrode being designated as an anode and the other being designated as a cathode, wherein said means for creating (24, 26, 36) are arranged to determine which electrode or electrodes of the array make up said at least two composite electrodes depending on the determined state of the wound and the wound healing system includes means for selecting said respective one or more electrodes of the array for forming the respective two composite electrodes (14a-14l) based on information concerning the state of the wound, the size, shape and/or location of said at least two composite electrodes (14a-14l) being determined respectively by the size, shape and /or location of the wound with respect to the array, the composition of said at least two composite electrodes being adjustable in response to changes in the determined state of the wound.