A dry powder inhaler suitable for pulmonary or nasal delivery, the inhaler comprises a cover, an inhaler body, a mouthpiece and a capsule tray, the inhaler body having: opposing upper and lower walls spaced apart to form a chamber within the body which constitutes an inhaler body opening, one end of the inhaler body being open by means of which the capsule tray is engageable into the inhaler body opening, cutting means (18, 19) provided on the upper and lower walls, which cutting means (18, 19) extend into the inhaler body opening, an inhalation passage formed in the upper wall of the inhaler body, and a first hinge segment; the mouthpiece having an inhalation passage and a second hinge segment, the mouthpiece and inhaler body having complementary locking means operable to secure the mouthpiece to the inhaler body when they are engaged together; characterised in that: the first hinge segment includes at least one bearing surface; the second hinge segment is complementary to the first hinge segment and includes at least one bearing surfaces, the mouthpiece being engageable with the inhaler body such that the first and second hinge segments engage with each other to form a hinge passage therebetween; the cover includes a third hinge segment formed by an axle carried on the cover, the axle being sized to be engageable in the passage formed between the first and second hinge segments so as to be rotatable within said passage and thereby enable pivoting movement of the cover relative to the inhaler body and the mouthpiece; the capsule tray is moveable in the opening through said open end between a first position in which the capsule tray is withdrawn from the opening so as to allow access to a capsule chamber formed therein for loading and unloading a capsule from the capsule chamber, and a second position in which the capsule chamber is aligned with the inhalation passage of the inhaler body to enable inhalation of the medicament contained in the capsule through the inhalation passage, the cutting means (18, 19) being positioned to engage the top and bottom of the capsule as the capsule tray is moved from its first position to its second position in order to cut openings in the top and bottom of the capsule, at least one of the inhaler body and the mouthpiece including stop means located within the opening which are engaged by the capsule tray as it is engaged into the opening to limit the travel of the tray 2 inside inhaler body opening; and the inhaler is assembled by seating the axle of the cover in the first hinge segment and then fitting the mouthpiece onto the inhaler body so that the second hinge segment engages over the axle and against the first hinge segment and locks in place, thereby forming a single, permanent, mechanically effective hinge. opposing upper and lower walls spaced apart to form a chamber within the body which constitutes an inhaler body opening, one end of the inhaler body being open by means of which the capsule tray is engageable into the inhaler body opening, cutting means (18, 19) provided on the upper and lower walls, which cutting means (18, 19) extend into the inhaler body opening, an inhalation passage formed in the upper wall of the inhaler body, and a first hinge segment; the first hinge segment includes at least one bearing surface; the second hinge segment is complementary to the first hinge segment and includes at least one bearing surfaces, the mouthpiece being engageable with the inhaler body such that the first and second hinge segments engage with each other to form a hinge passage therebetween; the cover includes a third hinge segment formed by an axle carried on the cover, the axle being sized to be engageable in the passage formed between the first and second hinge segments so as to be rotatable within said passage and thereby enable pivoting movement of the cover relative to the inhaler body and the mouthpiece; the capsule tray is moveable in the opening through said open end between a first position in which the capsule tray is withdrawn from the opening so as to allow access to a capsule chamber formed therein for loading and unloading a capsule from the capsule chamber, and a second position in which the capsule chamber is aligned with the inhalation passage of the inhaler body to enable inhalation of the medicament contained in the capsule through the inhalation passage, the cutting means (18, 19) being positioned to engage the top and bottom of the capsule as the capsule tray is moved from its first position to its second position in order to cut openings in the top and bottom of the capsule, at least one of the inhaler body and the mouthpiece including stop means located within the opening which are engaged by the capsule tray as it is engaged into the opening to limit the travel of the tray 2 inside inhaler body opening; and the inhaler is assembled by seating the axle of the cover in the first hinge segment and then fitting the mouthpiece onto the inhaler body so that the second hinge segment engages over the axle and against the first hinge segment and locks in place, thereby forming a single, permanent, mechanically effective hinge.