A pulsating therapeutic inhaler generating pneumatic pulses for treating respiratory disorders is disclosed. The aforesaid inhaler comprises: (a) a linear passage having an elongate axis the linear passage configured to conduct a fluid flow in a laminar manner (b) a patient interface fluidly connectable to the patient s respiratory tract having an aperture fluidly connectable to the passage and (c) a shutter disposed between the passage and the aperture configured to modulate a fluid pressure within the fluid flow the shutter comprising a disc having at least one cutout and rotating about an axis parallel to the passage axis. The cutout has four cornered perimeter thereof with two side portions and two circumferential arcs configured relative to the rotation axis. The side portions are circumferentially anti symmetrical relative to the aperture.
