A system for delivering a flowable, therapeutic composition, such as a flowable hemostat, biologics, or a medicine paste, includes a cannula having a proximal end with a proximal opening, a distal end with a distal opening, and an elongated lumen extending from the proximal end to the distal end. The flowable, therapeutic composition fills the elongated lumen of the cannula, and a piston is disposed within the elongated lumen for sealing the proximal end of the cannula. An end cap is secured to the distal end of the cannula. A pump assembly includes a fluid and is coupled with the proximal end of the cannula. After the end cap, is removed, the pump assembly is operable to pump the fluid for directing the fluid to flow through the proximal opening of the cannula to force the piston to slide toward the distal end of the cannula to express the flowable, therapeutic composition from the distal end of the cannula.