Telescoping syringe with one-way valve

A telescoping syringe suitable for use with medications and other flowable materials is presented. The telescoping syringe includes a one-way valve, a plunger, and a barrel. The valve includes a barrier, an outlet(s) through the barrier, and an annular extension extending from the barrier. The plunger includes an inlet(s) and a proximal wall fixed at one end of a first side wall. The valve directly contacts a distal end of the first wall so that an annular flange extending inward from the annular extension slidingly engages an annular groove along the first wall between first and second positions. The circumferential end of the first wall contacts the barrier in the first position to close the outlet(s). The circumferential end does not contact the barrier in the second position to open the outlet(s). A first reservoir is defined by the first wall, the proximal wall, and the valve. The inlet(s) permits gas to enter the first reservoir as fluid is transferred through the valve to a second reservoir. The barrel includes a second side wall with a nipple fixed to a distal wall at one end and an open end at another end. The plunger is extendable from and retractable into the barrel at the open end via slidable engagement between first and second walls. The second reservoir is defined by the distal wall, the second wall, and the valve.