Mixing devices and systems are disclosed for storing separate components and for mixing and dispensing those Components on demand. A mixing device includes a syringe having a generally tubular housing formed with a mixing chamber. A plunger is fitted to the tubular housing to form a first syringe. A dispensing syringe is releasably connected to the mixing chamber. At this point each syringe holds a desired amount of a mixture component. The contents of one syringe are passed through the mixing chamber to the other syringe, forming a usually incomplete mixture. The mixture is then passed through the mixing chamber to the other syringe. Multiple passes through the mixing chamber are continued until the desired mixing result is achieved, and the mixture material is contained in the second syringe that is used to thereafter dispense desired amounts of the mixture.