An ultrasonic surgical liposuction apparatus (20) comprises a piezoelectric crystal transducer assembly (24) which is connectable to an interchangeable operative probe (25) and tip (26). The probe (25) can be hollow, if aspiration of the fatty tissue is desired, or it can be solid. The tip is largely formed of a plastic material, to prevent the propagation of the ultrasonic waves to the distal end of the apparatus. Prevention of propagation of the ultrasonic energy to the distal end prevents unwanted damage of the tissues by an excessively hot tip. The tip (26) can be removable or permanently affixed by a weld. The tip (26) can have a metal jacket (28) covering the lateral surfaces (29) of the plastic tip body (27), to assist penetration of the fatty tissue, or the tip (26) can be entirely made of plastic. The tip (26) can also have an opening or series of openings (92) for aspiration of the fatty tissue.