A delivery device (100,200) is disclosed, which comprises a container (80) containing a dose of a powder and having at least one exit orifice (98) for dispensing the dose from the container (80), and a chamber (110) adapted to receive the container (80) in an operative configuration, the device (100,200) further comprising at least one gas inlet (26) by which gas may enter the chamber (110) and at least one gas outlet (72) by which gas and entrained powder may exit the chamber (110), wherein the delivery device (100,200) is operable to generate a gas flow through the chamber (110) between the at least one gas inlet (26) and the at least one gas outlet (72), which brings about orbital motion of the container (80) within the chamber (110) in that at least a central region of the container (80) orbits a central axis of the chamber (110), wherein the volume occupied by the container (80) is at least 25% of the volume of the chamber (110).
