An inhaler comprising a reservoir of an inhalable composition with an outlet at one end through which the inhalable composition is discharged. A non-metered breath-activated valve is provided between the one end and the reservoir, the breath-activated valve comprising a flow path extending from the reservoir to the outlet end. At least a portion of the flow path is a deformable tube. A clamping member pinches the deformable tube closed when no suction force is applied to the device and releases the tube to open the flow path when suction is applied at the outlet, to provide uninterrupted flow from the reservoir to the outlet.