A heat and moisture exchanger (IO) for tracheostomized or laryn-gectomized patients, having a valve plate and a housing, wherein: the valve plate has a radially surrounding lip, and the housing comprises a valve seat which encloses a distal opening of the housing, the valve seat has a groove for receiving the lip, the valve plate is associated with the distal opening of the housing, and the valve plate can be moved into a closed position in which the lip engages in the groove.