Abstract: A self defense ring device which ejects a noxious substance in the direction of an assailant when activated by a user. The invention includes a sealed ampoule containing a noxious substance or a combination of substances separated by membranes. This ampoule is driven forward by pressure within a closed chamber having an ejection outlet. The ampoule is pierced and collapsed by the pressure, ejecting the noxious substance or mixture of substances through the ejection outlet at high speed. This mechanism is appropriate for a wide variety of noxious substances. The ejection outlet is inconspicuously placed on the side or underside of the ring, aiding in concealing the self-defense function of the ring device.