Abstract: A breast pump includes a platform resting on the floor or other support and a treadle having a convex surface resting on the platform, permitting a pivoting or see-saw motion of the treadle. A bellows is connected between the treadle and the platform, forming a variable displacement chamber. A flexible hose connects the chamber to a reservoir including a container, such as a baby bottle, and an adaptor attached to the bottle as a cap. There is no valve controlling the flow of air to or from the reservoir, thereby providing complete and precise control of the pressure in the reservoir.