The present invention is a collapsible/expandable and disposable spacer for use with a metered dose inhaler (‘MDI’). One embodiment of the invention is a spacer collapsible into a substantially flat configuration for storage and expandable into a spacer volume for use with a metered dose inhaler (MDI) wherein the spacer comprises: (a) a collapsible and expandable panel arrangement internally located within the spacer volume to divide the spacer volume into a MDI medicament delivery chamber and an inhalation/exhalation chamber when the spacer is in an expanded configuration; (b) a medicament delivery opening adapted to receive a MDI in a MDI medication delivery end of the MDI medicament delivery chamber; (c) an inhalation opening in a mouthpiece end of the inhalation/exhalation chamber; (d) an exhalation opening in the inhalation/exhalation chamber; and further wherein the panel arrangement comprises an aperture off-set from the medicament delivery opening with the proviso that the aperture is not a valved aperture.