Ventilation valve for colostomy bags, comprising a valve body (1) in which a sheet (7) is orientable in order to make a ventilation hole (11) in the sheet coincide with an opening (4) in the valve body, comprising a pin or heel (9) on the face of the sheet that is oriented to the valve body characterized in that the opening of the valve body extends in the direction of movement of the sheet and the pin or heel extends into the opening of the valve body, said pin or heel (9) having a length less in the direction of the movement of the sheet than the opening of the valve body so that the sheet can move between an open position and a closed one, the opening of the valve body having an end area that is released by the stage, the pin or heel (9) having a shape and dimension corresponding to the shape and width of the end area for seal the contact in the closed position, and the pin or heel (9) being provided at its free end with an extension or a collar (10) protruding laterally which, on the side of the valve body that is oriented away from the sheet (7), is in contact with the valve body and when the valve is closed it extends a distance outside the opening (4) in the valve body so that, in addition, an area around the air passage is Keep free from contamination.Válvula de ventilación para bolsas de colostomía, que comprende un cuerpo (1) de válvula en el que una lámina (7) es orientable con el fin de hacer que un orificio de ventilación (11) en la lámina coincida con una abertura (4) en el cuerpo de válvula, comprendiendo un pasador o talón (9) en la cara de la lámina que está orientada al cuerpo de válvula caracterizada por que la abertura del cuerpo de válvula se extiende en la dirección del movimiento de la lámina y el pasador o talón se extiende dentro de la abertura del cuerpo de válvula, teniendo dicho pasador o talón (9) una longitud menor en la dirección del movimiento de la lámina que la abertura del cuerpo de válvula de manera que la lámina se puede mover en
