The present invention relates to a dose setting mechanism for a drug delivery device and a method of using same. The mechanism comprises a housing, a mechanism member movable in a first axial direction relative to the housing during dose setting and movable in a second, opposite axial direction relative to the housing during injection, wherein the mechanism member is designed and arranged such that the mechanism member is able to change its condition between a first condition preventing movement in the second axial direction and a second condition allowing movement in the second axial direction, and a switching member forcing the mechanism member to change from its second condition into its first condition at a predefined position of the movement in the first axial direction during dose setting.
