Poison

A poison is any substance that can cause severe distress or death if ingested, breathed in, or absorbed through the skin. There exists both an Antidote to Common Poisons that can counteract the effect of many ordinary poisons, as well as an Antidote to Uncommon Poisons that is helpful against many rarer ones. A bezoar is a stone taken from the stomach of a goat that will reverse the effects of most poisons, though there are certain unusual ones that it won't work against.

At some point, a poisoned vermin trap was set up in a room of Hogwarts Castle.

Three of the potions in the bottles of the sixth obstacle of the Philosopher's Stone chambers were poison. The riddle accompanying the bottles stated that the poison was deadly.

Slow-acting venoms were briefly mentioned in Gilderoy Lockhart's Gadding with Ghouls. Hermione Granger claimed that the contents of Moste Potente Potions would help her to understand what Lockhart had to say about this subject, though this was merely a ploy to obtain the book in order to find the instructions for brewing Polyjuice Potion. Whether or not this book actually contained infomation on slow-acting venoms is unknown.

On Valentine's Day in 1993, Lockhart suggested that students ask Severus Snape to show them how to whip up a Love Potion, but Snape looked "as though the first person to ask him for a Love Potion would be force-fed poison."

On 1 September of that year, following the inspection of the Hogwarts Express by Dementors, Remus Lupin handed out chocolate to Harry Potter and his friends to ward off the effects of the dementor's visit to their cabin, then went to speak with the train's conductor. When he returned and saw that none of them had eaten, he stated "I haven't poisoned that chocolate, you know."

According to an alleged British Ministry of Magic insider in The Quibbler article "How Far Will Fudge Go to Gain Gringotts?", poison was one of the methods that Minister for Magic Cornelius Fudge had employed to have goblins killed.

In addition to those brewed intentionally as poisons, certain types of potions could have poisonous effects if brewed incorrectly. Before testing Neville Longbottom's Shrinking Solution on Trevor, Severus Snape noted that if the potion had not been brewed correctly, Trevor would likely be poisoned. A sign posted at St. Mungo's Hospital for Magical Maladies and Injuries advised Healers that "A clean cauldron keeps potions from becoming poisons."

Alastor "Mad-Eye" Moody was well known for only drinking from his hip flask, due to the ease with which an unscrupulous wizard might poison an unattended cup.

In advising Harry Potter to continue Potions in his sixth year, Minerva McGonagall noted that poisons and antidotes are essential study for Aurors.

When attempting to interrogate Harry Potter as to the whereabouts of Albus Dumbledore and Sirius Black, Dolores Umbridge requested Veritaserum from Severus Snape. He replied that he had no further stocks of it. He blithely stated that he could not be any further help to her unless she wished to poison Harry, but noted that most venoms act too quickly to give the victim much time for truth-telling.

Ronald Weasley was once poisoned by a bottle of mead, that was supposed to be a gift to Albus Dumbledore from Horace Slughorn. He was saved with a bezoar by Harry Potter.

Appearances

 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Philosopher's Stone (video game)
 * Harry Potter and the Chamber of Secrets
 * Harry Potter and the Chamber of Secrets (film)
 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Half-Blood Prince (film)
 * Harry Potter and the Half-Blood Prince (video game)
 * The Tales of Beedle the Bard