Vulnera Sanentur

Vulnera Sanatur is a spell used to heal deep gashes. It is the counter-curse of Sectumsempra. The incantation, which sounds "almost like song," must be repeated three times in a row to have a full effect. The first time it is used, the flow of blood eases up; the second time causes the wounds to knit; the third time removes the worst effects of the curse near-instantly. The victim would still require medical treatment, and if dittany is applied immediately, scarring can be avoided.

Severus Snape used this spell to heal Draco Malfoy's wounds after Harry Potter cast Sectumsempra on him during a duel in the second-floor girls' lavatory in 1997.

Etymology
Vulnera Sanatur derives from Latin vulnero, "wound," and sanare, "to heal."

Appearances

 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Half-Blood Prince (film)