if you are exposed to the sectumsempra spell and your body is pierced like a chicken with a bottle, the nearest witch and wizard must cast this spell on you, otherwise you will get merlin from blood loss.
it comes from the latin word "vulnero" meaning wound and "sanare" meaning to heal. it is repeated 3 times. if dittany is applied immediately afterwards, no traces are left. but do not neglect to see a local doctor.