Leech juice is a fluid comprised of crushed and liquefied leeches. It's used in potion-making: in the Shrinking Solution a dash of leech juice is one of the ingredients (adding too much, however, causes the potion to turn orange instead of the bright acid green it's supposed to be; this can prove disastrous, as making errors in the potion can cause the mixture to become poisonous).
- Harry Potter and the Prisoner of Azkaban (First appearance)
- Harry Potter and the Prisoner of Azkaban (video game)
- The Road to Hogwarts Sweepstakes
- Wonderbook: Book of Potions