Potion to Cure Boils

A potion to cure boils is a simple potion that can be brewed from dried nettles, crushed snake fangs, stewed horned slugs and porcupine quills, which have to be added after taking the cauldron off the fire.

This is the first potion Harry Potter and his classmates learn at Hogwarts during their very first Potions lesson with Severus Snape on September 6, 1991. Neville Longbottom adds the porcupine quills before taking Seamus Finnigan's cauldron off the fire; with disastrous effects. Seamus' cauldron melts, acid green smoke fills the room and the potion seeps across the floor with a hissing noise, burning holes into the students' shoes. Neville's arms and legs, which were drenched in the potion when the cauldron collapsed, are covered in angry red boils. Snape orders Seamus to take him him to the hospital wing and deducts a point from Gryffindor. He blames Harry for the loss because the boy did not warn Neville about the quills