A device having a planar body with communicating flexible tubular members on its opposite sides having a one-way air valve therebetween may be used by a person performing mouth-to-mouth resuscitation on a second person such as in the practice of cardiopulmonary resuscitation commonly referred to as CPR. One of the flexible tubular members is designed to be positioned in the mouth of the person receiving the resuscitation and retained therein by portions of the planar body of the device being held against the person's lips and cheeks while the other of the flexible tubular members is positioned in the mouth of the person performing the mouth-to-mouth resuscitation. The one-way air valve controlling communication between the flexible tubular members is arranged to permit air to be delivered into the mouth of the person receiving the resuscitation and to prevent air from the receiving person's mouth from moving upwardly into the mouth of the person performing the mouth-to-mouth resuscitation. The device prevents saliva, phlegm, or other liquids from entering the mouth of the person performing the mouth-to-mouth resuscitation. The communicating flexible tubular members are designed to be collapsed into a small area to facilitate packaging of the device with the device being formed of a suitable synthetic resin or the like having sufficient resiliency to extend the flexible tubular members into usable positions when the packaging, which primarily maintains the device in sterile condition, is removed.