An inhalation device for use in delivering a powdered substance to a user, the inhalation device comprises a housing including a holding portion for holding the substance; an air entry passageway sized and configured to direct air entering the inhalation device at the portion and to fluidize the substance upon inhalation by the user; a hold-up chamber in flow communication with the holding portion for receiving the fluidized substance and maintaining the substance in a fluidized state during inhalation by the user; and an air exit passageway in flow communication with the hold-up chamber and adapted to deliver the substance to the user.