A dry powder inhaler may include at least one air inlet, at least one air outlet, an air channel between said air inlet and outlet, and at least one medicament reservoir. The inhaler may include a dosage mechanism for arranging at least one dose of a medicament from said medicament reservoir between the air channel and the air outlet such that said at least one dose may be delivered upon inhalation at said air outlet. The dosage mechanism may include a dose disc with at least one cavity, wherein the dose disc may be rotatable between a dose collecting position, in which the cavity may be positioned in the medicament reservoir, and a dose administering position, in which the cavity may lie underneath the air channel. The inhaler may also include a floor disc abutting the dose disc underneath the cavity to form a bottom of the cavity for radial emptying of the medicament from the cavity during inhalation. Alternatively, the inhaler may include a floor disc abutting the dose disc underneath the cavity to form a bottom of the cavity and support the medicament in the cavity, wherein said dose disc may rotate in relation to the floor disc when the dose disc is rotated between the dose collecting position and the dose administering position to grind any residual medicament in the cavity.