A spacer for use with a powdered medicament inhaler. The spacer comprises a slender curved body, which defines a chamber, an inlet communicating with the chamber and an outlet communicating with the chamber. The inlet and outlet are arranged so that in use an airstream passing from the inlet through the chamber to the outlet is caused by the slender curved body to following a rotational flow path. This selectively extracts particles of powdered medicament entrained in the airstream.
