An implantable electroacupuncture device (IEAD) treats a disease or medical condition of a patient through application of stimulation pulses applied at a specified acupoint or other target tissue location at a very low duty cycle. In a preferred implementation, the IEAD is an implantable, coin-sized, self-contained, leadless device having at least two electrodes attached to an outside surface of its housing, with at least one electrode on the top or bottom surface of the housing functioning as a cathode, and at least one electrode on the perimeter edge of the housing functioning as an anode. The electrodes may be segmented to include an array of smaller cathodic or anodic electrodes, each of which may be selectively turned ON or OFF so as to provide a convenient mechanism for adjusting the density of the stimulus current flowing through the cathodic electrode surface area.