Abstract: The present invention relates, in general, to ultrasonic surgical instruments and, more particularly, to an intracorporeal ultrasonic surgical instrument for sonodynamic therapy. Disclosed is an ultrasonic surgical system comprising: a generator and an instrument comprising: a housing; a transducer; a semi-permeable membrane; a pharmaceutical agent; and an agent delivery system. The transducer is adapted to convert the electrical energy of the generator into mechanical energy. The pharmaceutical agent, delivered into a chamber of the semi-permeable membrane, is driven through the semi-permeable membrane by the mechanical energy.