A breast pump is disclosed comprising a body (50) with an inlet (84) thereto to receive milk expressed from a woman's breast. The body is formed for releasable attachment to a container for collecting expressed milk and houses a deformable diaphragm (51) which is cyclicly moved by manually or electrically driven actuating means (53,54) connected thereto to generate and release cyclicly a negative pressure in the nipple region sufficient to stimulate the nipple area to cause lactation. The pump preferably includes valve means (80) mounted in the body so that said negative pressure is created in the pump body only and not in the container for the expressed milk when connected thereto. <IMAGE>
