A flexible endoscopic instrument is provided with a plurality of elastic ligating rings mounted on one tube of a pair of tubular members which are affixed in coaxial relation to the insertion end of an endoscope. The rings are adapted to be dislodged therefrom in sequence at selectively controlled times for treating multiple lesions during a single insertion of the endoscope into a body organ. The endoscope is equipped with illumination and viewing [means] apparatus to facilitate orientation of the instrument in the body organ, and longitudinally extending tubular passages comprising a channel through which objects may be passed and suction applied for drawing the lesion tissue into the tubular end of the endoscope to facilitate ligation of a lesion, and a working channel through which a flexible actuating cable is inserted. The cable is connected to one of the tubular members and serves to [as a means for] impart[ing] relative motion between the pair of tubular members to sequentially dislodge the elastic rings from the endoscope at controlled times. Each of the elastic rings can be dislodged from the endoscope and placed in ligating relation to a lesion when lesion tissue is drawn into the innermost of the tubular members by a suction force applied through the suction channel and each of the rings can be applied to a different one of the multiple lesions in the body organ during a single insertion of the endoscope.