Abstract: An inhaler for inhaling pulverulent medicament from within a capsule comprises a chamber (24) within which the capsule is free to rotate while having its longitudinal axis in the median plane of the chamber and thus generally parallel to the front and rear walls (30) and (31) of the chamber, by virtue of the fact that the spacing between said front and rear walls is less than the axial length of the capsule but just greater than the diameter of the capsule. The device includes pins (21) serving as opening means to pierce the ends of the capsule while it is seated in a recess (25), whereupon the retraction of the pins (21) allows the capsule to be entrained into swirling airflow in the chamber (24) during inhalation of air through air inlets (26) and out through a mouthpiece nozzle (27).