A syringe assist device for preventing vacuum stall in an infusion pump which extracts fluid medication from a conventional syringe. The device is a plunger housed within a front case and a back case. The plunger is comprised of a cocker, a cradle, and a base member. The cocker and cradle are compressively retained by a spring spanning therebetween. The cocker includes a locking member which cooperates with a wedge type locking member defined by the back case to prevent movement along the base member. The cradle includes a syringe barrel compression member. In its unlocked position, the cocker and the cradle slide against the base member in unison, while in its locked position, only the cradle slides against the base member, thereby enabling a unidirectional compressive force upon the syringe. By this compressive force, the vacuum created within the syringe during infusion is eliminated, thereby eliminating vacuum stall.