"Didn't I state plainly that a dash of leech juice would suffice?"
Professor Snape, needling Neville Longbottom about his Shrinking Solution[src]
Leech juice

A bottle with some leech juice

Leech juice is a fluid comprised of crushed and liquefied leeches.[1] 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).[2]


Notes and references