Abstract: A portable inhaler, has a rotary actuation mechanism, including a follower component (104), a rotary loading device (106) and a button (112). The rotary loading device has a cam component (108) engaged with a cage component (110), to allow a predetermined limited rotational relative movement therebetween. The button is translatable between a central position and an extended position, and can be engaged by the cam component upon rotary movement of the rotary actuation mechanism to its primed position to translate the button to its extended position, and the button can engage the cam component to effect rotary movement of the rotary actuation mechanism to its actuated position as the button translates to its central position thereby releasing the follower component.