The removable cap for a feeding bottle is made from flexible plastics material with a smooth exterior surface which is soft to a baby's lips and chin and has an upstanding nipple open at the bottom and with an aperture at the top. The underside of the cap is provided with a plurality of spaced shallow indentations elliptical in shape and moulded into the plastics material. The indentations are arranged in concentric circles around the open end of the nipple and increase in length and width progressively from the innermost circle to the outermost circle.