A medicine reservoir 10 is provided for use with a drug delivery device 50. The mediciae reservoir 10 is arranged for comprising a drug 13 and comprises a dispensing hole 15 for dispensing the drug 13 into an environment of the drug deUvery device 50. The medicine reservoir 10 further comprises a deformable plug 14 which plug 14 is removable by a pressure caused by a dispensing action of the drug delivery device 50.