A resettable drive mechanism for a medication delivery device comprising a housing and a drive member rotatable in a second direction for delivering a dose. A piston rod driven distally when a drive member rotates in the second direction. A stop member prevents rotation of the drive member in a first direction opposite the second direction, when the stop member engages the drive member. A clutch member is movable between a delivery and reset position. When the clutch member is in the delivery position, the stop member and the drive member engage and the drive member is prevented from rotating in the first direction. When the clutch member is in the reset position, the drive member and the stop member disengage. The drive member is rotatable in the first direction.