A syringe is provided for the delivery of controlled, metered amounts of any of numerous different substances to humans or animals, such as medicaments, pharmaceuticals, cosmetics, and food products, or to deliver materials which may react upon exposure to air, such as glue. The syringes include a body and a plunger. Means are provided in the syringe body and the plunger to effect controlled movement of the plunger into the syringe to permit delivery of a pre-determined amount of the substance contained in the syringe. A one-way valve is provided at the dispensing tip of the syringe to hermetically seal the portion of the syringe containing the substance to be dispensed.