A medical device for electrical stimulation of a patient. A pulse generator generates current pulses for the electrical stimulation. An electrode lead with a plurality of electrode contacts delivers the pulses to tissue of the patient. The pulse generator repeatedly delivers a current pulse between two electrodes forming a first group and delivers a charge balancing current pulse after each current pulse between the electrodes of the first group. The respective current pulse is separated from the succeeding charge balancing current pulse by an inter pulse interval. The respective current pulse has an amplitude with the same absolute magnitude as the succeeding charge balancing current pulse, but is of opposite sign. The pulse generator delivers between each current pulse and the succeeding charge balancing current pulse a current pulse between two further electrodes forming a second group of electrode contacts of the plurality of electrode contacts.