This Quirk allows Chiyo to amplify and speed up a person's healing process by extending her lips and kissing them. With this, some grave injuries requiring months to heal can be healed completely in a matter of seconds.
The healing process, however, is not without its cost. It requires stamina from the receiver's part in order to work, leaving the said receiver very exhausted after the process is completed if an injury is, or injuries are, serious enough. It might also lead to their death if the amount of stamina they've are less than what is needed to heal their injuries. As such, surgeries and conventional healing methods will be required for severely life-threatening injuries, before the effects of the Quirk can be applied. In such cases, it is sometimes applied several times over a period of time, instead of healing everything in one shot.