Abstract: Protective underwear made of air-tight polyurethane-coated nylon (10) with elastic sewn around the waist (12) and around the bifurcated legs (14a, 14b). An exit hole (24) for the flatus is cut from the back, near the bottom, of the underwear. The exit hole is covered with a pocket (16a, 16b) made of porous fabric, and designed in the same shape as the exit hole (24), only larger. The bottom layer of the pocket (16b) is sewn (22) around the edge of the exit hole (24) connecting it to the underwear. The top layer (16a) is sewn (20) around the edge of the bottom layer (16b) and onto the underwear, except at the top, leaving the pocket opening. The pocket opening is kept closed by a fastener. The replaceable filter is large all around than the exit hole (24), but smaller all around than the pocket (16). The top and bottom layers are of wool felt (26a, 26b); and both layers are cut larger than all other layers to facilitate sewing (28).