An inhaler (1) comprising a housing (2) to receive a plurality of blisters (6a) each having a puncturable lid (6c) and containing a dose of medicament for inhalation by a user is disclosed. It comprises a mouthpiece (5) through which a dose of medicament is inhaled by a user, an actuator (3) and, a cap (4,43)coupled to the actuator. The cap is rotatable to sequentially move each blister into alignment with a blister piercing member (9,10,11) and the actuator is operable, in response to rotation of the cap, to cause the blister piercing member to puncture the lid of an aligned blister. When a user inhales through the mouthpiece, an airflow through the blister is generated to entrain the dose contained therein and carry it out of the blister and via the mouthpiece into the user's airway.
