Basilisk venom is extremely powerful, and can kill a person within a little more than a minute at best, making the person drowsy and blurry-visioned before they die. The strength of the venom is one of the few substances known to be capable of destroying Horcruxes, causing them fatal damage that cannot be repaired. It only has one known antidote: phoenix tears, which happens to be very rare, increasing the venom's deadliness.
In 1993, Harry Potter stabbed the roof of the basilisk's mouth with Godric Gryffindor's Sword and ended up getting a fang splintered into his arm. Tom Riddle described the venom as being able to kill Harry in a little more than a minute, though Fawkes's tears healed Harry's arm and cleansed the poison.
After being healed, Harry took the fang and stabbed Riddle's diary, destroying that Horcrux beyond magical repair. Because Harry had stabbed the Basilisk with the sword, it was imbued with Basilisk venom and was therefore able to destroy Horcruxes and poison opponents that it cuts through as well.
In 1998, during the Battle of Hogwarts, Ron and Hermione went down to the Chamber of Secrets and destroyed Helga Hufflepuff's Cup with a basilisk fang. Neville Longbottom used Gryffindor's Sword to kill Nagini.
- Harry Potter and the Chamber of Secrets (First appearance)
- Harry Potter and the Chamber of Secrets (film)
- Harry Potter and the Chamber of Secrets (video game)
- Harry Potter and the Half-Blood Prince (Mentioned only)
- Harry Potter and the Deathly Hallows
- Harry Potter and the Deathly Hallows: Part 2
- Harry Potter and the Deathly Hallows: Part 2 (video game)
- LEGO Harry Potter: Building the Magical World (As basilisk fang)
- LEGO Harry Potter: Characters of the Magical World (As Basilisk fang)
- LEGO Harry Potter (As Basilisk fang)
- LEGO Harry Potter: Years 1-4 (As Basilisk fang)
- LEGO Harry Potter: Years 5-7 (As Basilisk fang)