Abstract: A one-way valve is illustrated that comprises a passageway in the feeding bottle of a baby or infant and a relatively flexible wall that is installed adjacently to the passageway so as to cover the passage. The passageway and the flexible wall establish a one-way valve that alternates between a state in which there is aerodynamic communication between the exterior and the interior of the feeding bottle and a state in which the aerodynamic communication is prevented. The one-way valve equalizes the pressures and facilitates the sucking action of the baby or infant.