Experiments were performed to define the contribution of the cellulose component in cigarette-filler to the organoleptic qualities of smoke. Pure cellulose shreds added to leaf tobacco gave the smoke a harsh quality readily detected by the smoker. Similar amounts of cellulose powder and tobacco dust, homogenized together and made into a film which was then used as cigarette filler, did not show the harshness effect even up to levels of 44 % added cellulose content in the mixture. Presoaking the cellulose paper in aqueous tobacco solubles also prevented the harshness in smoke observed from pure cellulose shreds. It was concluded that the intimate mixture of noncellulosic components with the cellulose in tobacco lamina and stems to a large extent modifies the burning of the cellulose component from that of pure cellulose paper. Chemical analyses showed that the manner of cellulose addition influenced appreciably the cigarette-smoke composition, thus accounting qualitatively for the organoleptic changes noted.