A resettable drive mechanism for a medication delivery device comprising a housing, a drive member rotatable with respect to the housing in a second direction for delivering a dose of a medication, and a piston rod by the drive member, when drive member rotates in the second direction, a stop member adapted to prevent rotation of drive member in a first direction, when the stop member engages the drive member, a clutch member movable between a delivery position and a reset position. When clutch member is in the delivery position, stop member and drive member are engaged and drive member is prevented from rotation in the first direction, and when the clutch member is in the reset position, the drive member and the stop member are disengaged, the drive member is rotatable in the first direction.
