Everyone with children has kissed a small bruise or cut to make it better.
This comes from one of our earliest medical procedures for the treatment of snakebite.
Noticing that a victim could be saved if the venom was sucked out through the point of entry, early doctors soon began treating all infectious abrasions by putting their lips to the wound and sucking out the poison.
Medicine moved on, but the belief that a kiss can make it all better still lingers.