An active molecule delivery system whereby active molecules can be released on demand and/or a variety of different active molecules can be delivered from the same system and/or different concentrations of active molecules can be delivered from the same system. The active delivery system includes a plurality of microcells, wherein the microcells are filled with a medium including an active ingredient and charged or magnetic particles. The microcells include an opening, and the opening is spanned by a porous diffusion layer. Because the porous diffusion layer can be blocked with the charged or magnetic particles, the rate at which the active ingredient is dispensed can be controlled with an electric or magnetic field, respectively.