The horn of a unicorn had magical properties that made it a useful ingredient in potions, such as the Antidote to Common Poisons. In classical myths, unicorn horns had purification properties which were used to dissolve poisons. This could be why it was used in the Antidote to Common Poisons.
There was a lively Muggle trade in unicorn horn, which they believed to have medicinal properties. However, most of these supposed horns were fake, and the few real ones that did pass into Muggle possession were useless to non-wizards.
- In 1991, unicorn horns were sold at the Apothecaries in Diagon Alley for twenty-one Galleons each.
- In the 1991–1992 school year, first year students at Hogwarts School of Witchcraft and Wizardry used unicorn horn in their Potions classes.
Behind the scenes
- It is likely that under normal circumstances horns are only taken from unicorns that have already died, since Firenze remarks that "it is a monstrous thing, to slay a unicorn". It may also be possible that the horn can be taken without killing the unicorn, perhaps if they shed and regrow them much like deer do antlers, or that only a small part of the horn is taken from a living unicorn.
- Harry Potter and the Philosopher's Stone (First appearance)
- Harry Potter Trading Card Game
- Harry Potter: The Character Vault (Mentioned only)
- Harry Potter: The Creature Vault