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"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."
— Description[src]

Sectumsempra was a curse invented by Professor Severus Snape that lacerates the target and causes severe haemorrhaging.[1] Snape created it as a student of Hogwarts, with the intention of using it against his enemies, likely including the Marauders, and it became one of his specialities.[3]



"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, when he was known as "The Half-Blood Prince".[6] He created it to retaliate against his enemies such as the Marauders,[7] and he recorded it in his N.E.W.T.-level Potions textbook.[8] He used it enough for Remus Lupin to recognise it as one of his signature spells.[3]

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."[9]

1996–1997 school year

Draco Malfoy: "Cruci-"
Harry Potter: "SECTUMSEMPRA!"
— Harry, using the curse on Draco[src]

Many years later, in the 1996–1997 school year, Harry Potter came into the possession of Snape's textbook and learned the incantation. Knowing nothing more than that it was "for enemies" 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. He expected humorous effects, as he had found with Levicorpus and other spells in the book.[8]

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

Harry initially considered using it against Cormac McLaggen for annoying him, though it was not until he confronted Draco Malfoy in the sixth-floor boys' bathroom that he tested it, seriously wounding Malfoy. Snape intervened to heal Draco, and having realised that Harry got a hold of his old textbook, he punished Harry with a multitude of detentions; though for fear of exposing himself as the curse's inventor, Snape chose not to turn Harry in for greater punishment.[1]

Despite disliking Malfoy, Harry did not want to harm him to such an extent, and was both horrified and guilt-ridden for using the curse against him, while reprimanding the Prince within his mind for adding such a deadly spell into his notes. Professor McGonagall considered Harry to be lucky not to have been expelled for such an act and full-heartedly supported the detentions, while Pansy Parkinson wasted no time in vilifying Harry far and wide; Ginny Weasley, however, stood up for Harry's usage of the curse, as it saved him from being struck by Malfoy's Cruciatus Curse.[1]

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, one spell Harry used was the Sectumsempra Curse, but it merely slashed their unfeeling flesh and did not seriously impede their approach.[10] Later that night, after Snape murdered Dumbledore, Harry attempted this curse against him, only for Snape to block it and angrily reveal to Harry that he was its inventor.[6]

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 after losing an ear due to Snape's misfired Sectumsempra curse

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.[11] 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.[3] 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.[11]


"Apparently I underestimated you, Potter. Who would have thought you knew such Dark Magic? Who taught you that spell?"
— Severus Snape to Harry Potter, regarding the power of this curse[src]

A rather dangerous curse, when the incantation was uttered its effect was the equivalent of an invisible sword; it was used to slash the victim from a distance, and resulted in deep wounds. The slash followed the user's wand movements.[1] Due to the depths of the cut, victims of this curse ran the risk of dying from blood loss if treatment was not applied in time, and if the wounds were not instantly fatal.[1][3]


The curse's effects followed the path of the caster's wand movements, hence if the user slips in their movement, it could either miss or cause an unintended target to be struck, as in the case of the aforementioned incident when Snape accidentally cut off George Weasley’s left ear due to a slip in his firing. [3][11]

While the curse could inflict damage on even undead such as Inferi, such targets had long since lost all sensation and blood and would not to react to pain and injuries, rendering the curse mainly pointless against them.[10]

Counter and treatment

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

Minor wounds inflicted by this curse can be cured by the song-like incantation Vulnera Sanentur; the first usage eased the blood flow, the second caused the wounds to knit and the third removed the worst effects of the curse.[1] The victim would still require medical treatment,[1] and if dittany was applied immediately, scarring can still be avoided.[3]

Though the aforementioned healing spell may have healed the wounds and essence of dittany may have prevented scars, any body parts that had been severed by this curse could not 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.[3]

Known uses


"Snape had directed his wand straight at James; there was a flash of light and a gash appeared on the side of James's face, spattering his robes with blood."
— Severus Snape cursing James Potter with this spell[src]
Caster(s) Victim(s) Date Note
Severus Snape James Potter I June, 1976 Used it to injure him, after James and Sirius Black started to bully him after an Ordinary Wizarding Level exam.[12]
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.[3][11]
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.[1]
Inferi 29 June, 1997 Used it against an army of Inferi that guarded the Cave, though they were unimpeded as they no longer feel pain or blood loss.[10]


Caster(s) Victim(s) Date Note
Harry Potter Severus Snape 29 June, 1997 Attempted the curse on Snape during the Battle of the Astronomy Tower, but Snape saw through it and preemptively stopped it. Snape was particularly furious that Harry would be using his own inventions against him.[6]
Robyn Thistlethwaite A copy of The Monster Book of Monsters September, 2008 Tried out the curse, but only angered the book.[13]

Known practitioners


The incantation Sectumsempra derives from the two Latin words: sectum, a participle of the verb sĕco , "to cut", and semper, meaning "always" or "ever". Since English has many words meaning "cut" or "lacerate", and since spell-names lend themselves to both infinitive and gerund verb forms ("to cut" and "cutting"), Sectumsempra can be translated in more than one way: "cut always", "ever cutting", "always sever", "ever severing", and so forth. "Sever" for sectum may be regarded as a particularly appealing translation in that "sever" creates a pun on Snape's first name, Severus.

Behind the scenes

The spell's icon as seen on Pottermore


Notes and references

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 Harry Potter and the Half-Blood Prince, Chapter 24 (Sectumsempra)
  2. 2.0 2.1 Harry Potter and the Half-Blood Prince (film) - Chapter 20 (Sectumsempra)
  3. 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 Harry Potter and the Deathly Hallows, Chapter 5 (Fallen Warrior)
  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. Pottermore - All about... Severus Snape
  6. 6.0 6.1 6.2 6.3 6.4 Harry Potter and the Half-Blood Prince, Chapter 28 (Flight of the Prince)
  7. As the book says "For 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.
  8. 8.0 8.1 Harry Potter and the Half-Blood Prince, Chapter 21 (The Unknowable Room)
  9. Harry Potter and the Goblet of Fire, Chapter 27 (Padfoot Returns)
  10. 10.0 10.1 10.2 Harry Potter and the Half-Blood Prince, Chapter 26 (The Cave)
  11. 11.0 11.1 11.2 11.3 11.4 Harry Potter and the Deathly Hallows, Chapter 33 (The Prince's Tale)
  12. 12.0 12.1 Harry Potter and the Order of the Phoenix, Chapter 28 (Snape's Worst Memory)
  13. 13.0 13.1 Harry Potter: Magic Awakened
  14. Harry Potter and the Half-Blood Prince (film) (see this image)
  15. Harry Potter and the Half-Blood Prince (film) (see this image)