A system for dispensing a medium includes at least a first container to hold the medium, a pressurizing device, such as a pump, in fluid connection with the container for pressurizing the medium, and an agitation mechanism or device to maintain the components of the medium in a mixed state. The container and the pressurizing device can be separate units, as in the case of an bag or bottle in fluid connection with a peristaltic or other type of pump. The container and the pump can also be combined in a single unit, as in the case of a syringe, wherein the syringe barrel of the syringe acts to contain the medium and the syringe plunger pressurizes the medium within the syringe barrel. A method of injecting a multi-component medium includes the step of agitating the medium (for example, as described above) before or during an injection procedure to maintain the components of the medium in a mixed state.