A control unit for a dressing for treating damaged tissue via a pair of electrodes. An electric current passes between the electrodes through the gel to repair the damaged tissue. Sensors can be incorporated into the dressing along with a control unit. The control unit can vary current supplied to the electrodes. One or more pre-defined programmes can be stored in the control unit for supplying an alternating current to the electrodes with a varying amplitude, frequency and waveform.
