A drug mixing and expelling device (1) for mixing a drug with a liquid, thereby forming a reconstituted liquid drug. The device comprises a reservoir (2) containing a liquid, a vial (4) containing a drug, a vial, means (5) for establishing a fluid connection between the reservoir and a vial positioned in the vial adapter (3), means (7, 8) for forcing the liquid from the reservoir to a vial, and means (9) for activating said forcing means during establishment of the fluid connection between the reservoir and the vial. The forcing of liquid into the vial provides a pressure therein, which can be used for infusion of the reconstituted drug directly from the vial. The device also comprises a suction unit (13) for aspiration.