"Blood spurted from Malfoy's face and chest as though he had been slashed with an invisible sword. He staggered backward and collapsed onto the waterlogged floor with a great splash, his wand falling from his limp right hand. Slipping and staggering, Harry got to his feet and plunged toward Malfoy, whose face was now shining scarlet, his white hands scrabbling at his blood-soaked chest."

Sectumsempra is the incantation of a curse invented by Professor Severus Snape that lacerates and subsequently haemorrhages the target. He created it during his childhood, when he was known as "The Half-Blood Prince"[5], with the intention of using it against his enemies, likely including the Marauders[6] and it became one of his specialties.[7]



"You dare use my own spells against me, Potter? It was I who invented them ~ I, the Half-Blood Prince!"
Severus Snape telling Harry Potter that he is the prince[src]

The spell copied down in Advanced Potion-Making

The curse was invented by Severus Snape and recorded during his time as a student at Hogwarts,[5] for use in retaliation against his enemies such as the Marauders.[6] He recorded it in his N.E.W.T.-level Potions textbook and used it enough to allow Remus Lupin to recognise it as one of his signature spells.

1996–1997 school year

Draco Malfoy: "Cruci-"
Harry Potter: "Sectumsempra!"
— Harry, using the curse on Draco
Many years later, in the 1996–1997 school year, Harry Potter came into the possession of Snape's textbook, and learned the incantation. Without knowing its effects at the time and believing that the "Half-Blood Prince" (Snape's nickname signed into the book) merely copied it as a note of reference, Harry became interested in trying it, thinking it would have humorous effects, similar to Levicorpus and other spells found within the same book.[8]

The end result of Harry's duel with Draco Malfoy after the use of Sectumsempra

Harry considered using it against Cormac McLaggen for annoying him, though it was not until he confronted Draco Malfoy in Sixth-floor boys' bathroom that he utilised it, seriously wounding Malfoy. Snape intervened to heal Draco, and having realised that Harry got a hold of the old textbook, he punished Harry with a multitude of detentions; Snape did not turn Harry in for a deeper punishment for fear of exposing himself to be the inventor of the curse. Harry, despite disliking Malfoy, did not truly want to harm Malfoy to such an extent, and was both horrified and guilt-ridden by using the curse against him. Professor McGonagall considered Harry to be lucky not to have been expelled for such an act, and she full-heartedly supported the detentions, while Pansy Parkinson wasted no time in vilifying Harry far and wide.[2]

During Harry and Dumbledore's hunt for a Horcrux, Harry accidentally attracted the attention of an army of Inferi. In an attempt to stop them, Harry used many spells, including Sectumsempra. The result of this merely slashed their unfeeling flesh, and created no serious impediment to their approach.[9] Later the same night, when Snape murdered Dumbledore, Harry attempted this curse against him, only for Snape to block it and angrily reveal to Harry that he was the inventor.[5]

1997–1998 school year

Remus Lupin: "He lost an ear."
Hermione Granger: "Lost an..."
Remus Lupin: "Snape's work."
— Lupin and Hermione discuss Snape's handiwork with the curse[src]
George ear

George lost an ear due to Snape misfiring Sectumsempra

The next year, during the Battle of the Seven Potters, Snape attempted to use the curse to sever the hand of a fellow Death Eater, but due to a slip, he accidentally cut off George Weasley's left ear instead, leaving him guilt-ridden. The Order of the Phoenix was not able to regrow the ear, as curse wounds (especially those in the nature of the Dark Arts), are unable to be healed, and the counter curse was unknown. Due to the nature of the events at the time, the Order believed Snape acted on ill-intent, and their grudge against him intensified, until Snape revealed his misfiring, posthumously, via his memory to Harry.[7][10]


A rather dangerous curse, when the incantation is uttered its effect is the equivalent of an invisible sword; it is used to slash the victim from a distance, and results in deep wounds. The slash follows the user's wand movements.[2] Due to the depths of the cut, the victims run the risk of dying from blood loss if treatment is not applied in time and if the wounds aren't instantly fatal.[2][7]


The curse's effects follows the path of the caster's wand movements, hence if the user slips in their movement, it can either miss or cause an unintended target to be struck.[7][10]

While the curse can inflict damage on even undead such as Inferi, such targets have long since lost all sensation, blood and will to react to pain and injuries, rendering Sectumsempra mainly pointless against them.[9]

Counter and treatment

Healing spell

Snape healing the damage the curse has done, using Vulnera Sanentur

Minor wounds inflicted by this spell can be cured by the song-like incantation Vulnera Sanentur;[3] the first usage eases the blood flow, the second causes the wounds to knit and the third removes the worst effects of the curse.[2] The victim would still require medical treatment, and if dittany is applied immediately, scarring can still be avoided.

Though the aforementioned healing spell may heal the wounds and essence of dittany may prevent scars, any body parts that have been severed by this curse cannot be grown back (a trait of dark magic's permanent effects), as demonstrated by George Weasley when he lost his left ear to the spell.[7]

Known uses

Successful uses

Caster(s) Victim(s) Date Note
Severus Snape James Potter I June, 1976 Used it to hurt him, after James and Sirius Black started to bully Severus after O.W.L.s. exam.[11]
George Weasley 27 July, 1997 Used it to sever the hand of a fellow Death Eater, who had been aiming at Remus Lupin's back during the Battle of the Seven Potters, but due to a slip, he accidentally cut off George's left ear instead, leaving him guilt-ridden.[7][10]
Harry Potter Draco Malfoy Early May, 1997 Used it to seriously wound him without a clear idea of what the effects would be, after he found the Half-Blood Prince's copy of Advanced Potion-Making that contained this spell.[2]

Known practitioners


Sectumsempra derives from the Latin sectum, "having been cut" (comparable to the English word "section" or "dissect"), and possibly semper, "always." It can be translated as "always cutting" or "sever forever", the latter being a pun on Snape's first name, Severus, as well as indicating that severed body parts cannot be regrown.

Behind the scenes

  • This curse's effect is similar to the Severing Charm, except it is used for more malicious intent and causes more slash-like wounds.
  • It is unknown when Severus Snape invented this spell, but according to Sirius Black, Snape "knew more curses when he arrived at school than half the kids in seventh year."[12]
  • Snape's invention of Sectumsempra was not likely a secret as Remus Lupin is able to recognise it during the Battle of the Seven Potters.
  • It's possible that Snape cast this curse against James Potter during their fifth year at Hogwarts after the Marauders publicly humiliated him, however this is unlikely since effects were not as extreme as they were when the spell was used against Draco Malfoy and George Weasley.
  • In the films, Sectumsempra appears as a small flash of white light launched forward like many spells, which causes a cut when it strikes the target. As a result, Harry only slashed Draco once across the chest, as opposed to the face as well.
  • In LEGO Harry Potter: Years 5-7, Harry uses Sectumsempra on Malfoy only to find out the spell has, apparently, painlessly sliced him in half.
  • In Harry Potter and the Deathly Hallows: Part 2, Voldemort may have used this spell to slit Snape's throat before having Nagini finish him off. The effect of Voldemort's use of the spell was a slash of the Elder Wand and it cut Snape's throat. In the film, Voldemort uses his wand itself to slash Snape's throat, in keeping with his occasional fondness for non-magical violence in that particular film.


Notes and references

  1. 1.0 1.1 Pottermore
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Harry Potter and the Half-Blood Prince, Chapter 24 (Sectumsempra)
  3. 3.0 3.1 Harry Potter and the Half-Blood Prince (film)
  4. Harry Potter and the Half-Blood Prince, Chapter 12 (Silver and Opals) - "Harry had already attempted a few of the Prince’s self-invented spells."
  5. 5.0 5.1 5.2 5.3 Harry Potter and the Half-Blood Prince, Chapter 28 (Flight of the Prince)
  6. 6.0 6.1 As the book says "for use on enemies", and the Marauders were the ones he hated the most as they constantly bullied him, it is highly likely they were the enemies he meant.
  7. 7.0 7.1 7.2 7.3 7.4 7.5 7.6 Harry Potter and the Deathly Hallows, Chapter 5 (Fallen Warrior)
  8. Harry Potter and the Half-Blood Prince, Chapter 21 (The Unknowable Room)
  9. 9.0 9.1 Harry Potter and the Half-Blood Prince, Chapter 26 (The Cave)
  10. 10.0 10.1 10.2 Harry Potter and the Deathly Hallows, Chapter 33 (The Prince's Tale)
  11. Harry Potter and the Order of the Phoenix, Chapter 28 (Snape's Worst Memory)
  12. Harry Potter and the Goblet of Fire, Chapter 27 (Padfoot Returns)
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