Abstract: An anal filter for protecting underwear from soiling, is attached to a person's anus solely by non-adhesive adherence to the anus and adjacent portions of the buttocks, due to a facing of fluffy fibrous material, and when attached, serves as a filter by being pervious to the discharge of gas through the anus but substantially impervious to complete passage of excreta carried by the gas or remaining on the anus from a bowel movement. A layer may be adhesively secured to the fibrous material and which prior to use of the anal filter can be pulled off from the fibrous material while pulling this material's fibers outwardly so as to give the material its fluffy characteristic.