A warming unit and method for warming an infusion medium prior to introducing the medium into a patient's body. The apparatus includes an outer casing, inlet and outlet tubes secured to the outer casing, a fluid conduit for transporting the infusion medium through the warming unit, and a heating element disposed proximate to the fluid conduit for warming the infusion medium flowing therethrough. The warming unit can form part of a system, which further includes a controller for controlling various functions of and separate from the warming unit, a reservoir containing the infusion medium, and a power source for powering the warming unit.