A dry powder inhaler comprises a mouthpiece (12) through which in use a user can inhale a powdered medicament. A mouthpiece obstruction or cover (6, 8) is arranged to prevent a user properly inhaling through the mouthpiece. A plurality of medicament doses are provided in individually sealed compartments (24). The inhaler has means (48, 50) for breaching the seal (25) of one of said compartments (24) to establish a pathway between that compartment and the mouthpiece, wherein the mouthpiece obstruction or cover is mechanically coupled to the seal breaching means so as to operate the latter when the mouthpiece obstruction or cover is opened. The inhaler further comprises one or more piercers (52, 54). The piercers are so shaped and arranged that upon penetration of the sealing member they form a hollow tube therewith for communicating with the interior of the compartment.
