Abstract: A medical pump comprises a casing having side walls, a peripheral wall, and a pump chamber defined thereby, an inlet port formed substantially in the central portion of one of the side walls of the casing, an outlet port formed in the peripheral wall of the casing so as to extend tangent thereto, a rocker substantially concentric with the inner peripheral surface of the casing and disposed in the chamber, and a rocker driving unit for rocking the rocker so as to vary the volume of the space between the rocker and the outlet port with the lapse of time, thereby producing a rotating flow in fluid in the casing.