there is provided a biodegradable filter tow or filter material from renewable raw materials for the use as a tobacco smoke filter element of cigarettes , cigars or pipes as well as a method for preparing it , wherein fibers , films or foams prepared in an extrusion method from biopolymers based on thermoplastic starch or its polymer compositions are processed to the filter tow or filter material according to the present invention . the advantages of this invention reside in the use of mainly renewable raw materials , a fast and complete biodegradability of the natural biopolymer filter material , a pollutant - reducing flavor - increasing filtering effect and an economically favorable preparation method .