Abstract: A drug delivery device is described which utilizes gas pressure from free oxygen and hydrogen derived from the electrolysis of water at the electrodes in negatively charged polymeric hydrogels by electro-osmosis. The gas pressure forces the infusion of the drugs through appropriate means into the body. The rate of electrolysis which produces the oxygen and hydrogen is controlled by an electric current. Therefore the rate of drug delivery can be predetermined and precisely controlled. The current is activated and controlled by an electronic timer or a biomedical control system. The negatively charged hydrogel polymers have mechanical strength and rigidity and allow water to flow through the polymer network toward the cathode ensuring a continuous water supply to the electrodes inside the hydrogel system by electro-osmosis. The hydrogels may be recharged (reswollen) with water or simply replaced.