Polyjuice Potion

Polyjuice Potion is a very complicated potion that allows the drinker to assume the form of someone else. While it can account for both age and gender, Polyjuice Potion cannot be used for a human to take an animal form or for a half-breed to assume human form. It was used many times in the events leading up to, and during, the Second Wizarding War (and possibly the First Wizarding War, although there are no documented instances of it). The potion also played a crucial role in Harry Potter, Hermione Granger, and Ron Weasley's investigation of the Chamber of Secrets in their second year. It was also used in Draco Malfoy's plot to smuggle Death Eaters into Hogwarts School of Witchcraft and Wizardry in 1997, in the Battle over Little Whinging, and in Harry, Ron, and Hermione's Infiltration of the Ministry of Magic and their break-in of Gringotts Wizarding Bank in 1998.

Ingredients

 * 1) 12 lacewing flies that have been stewed for 21 days
 * 2) 1 ounce of crude Antimony
 * 3) 4 leeches that have been "unsucculated"  (possibly meaning their suckers have been removed)
 * 4) 16 scruples of fluxweed that were picked at full moon
 * 5) 3 drachms of pulverised Sal Ammoniac
 * 6) Pulverised blades of knotgrass
 * 7) 1 pinch of powdered horn of a Bicorn that has been "lunar extracted"  (possibly meaning that, like the fluxweed, its collection time coincided with certain lunar conditions)
 * 8) Filings and rasplings of Saltpeter, Mercury and Mars ("filings of Mars" may mean iron filings, as the symbol for the planet Mars, ♂, is also used to signify the element of iron )
 * 9) Shredded dried skin of a Boomslang
 * 10) Extract of The-Transfigured-Being-To-Be  (which means a piece of the person one wants to change into, typically hair)

Most of the ingredients are available in the students' cupboard at Hogwarts, although some of them are only available in Severus Snape's private stores. It takes at least one month to brew properly.

Appearance
"“Ooh, you look much tastier than Crabbe and Goyle, Harry,” said Hermione, before catching sight of Ron’s raised eyebrows, blushing slightly, and saying, “Oh, you know what I mean – Goyle’s potion looked like bogies.”"

- Before Hermione Granger took on Harry's appearance for the Battle over Little Whinging



A piece of the person who is to be imitated — usually hair — is needed for the transformation. Before this final ingredient is added, Polyjuice looks like thick, dark mud that bubbles slowly. When the piece of the person to be imitated is added, however, the potion changes colour; it seems to react according to the nature of the person to be imitated, once even described as the 'essence' of the person. Good-hearted people result in more attractive colours and tastes, while mean people cause the opposite effect. Harry Potter's was a pure golden colour, whereas Gregory Goyle's tasted like "overcooked cabbage" and "looked like bogies" , Bellatrix Lestrange's tasted "disgusting, worse than Gurdyroots" and Mafalda Hopkirk's was a pleasant heliotrope colour. It is likely that the taste differs from potion to potion.

Effects
The effects of a single dose last for an hour, however the larger the dose the longer the effects last as seen in 1997 and 1998 when Harry Potter, Ronald Weasley, and Hermione Granger repeatedly take large doses of Polyjuice potion to facilitate them on the Horcrux hunt.

If a person dies while under Polyjuice Potion, as Mrs. Crouch did, then they will retain the form of whoever they have transformed into, rather than reverting back to their original shape.

Polyjuice can be used by a person to transform into someone of the opposite gender. It appears to adapt to account for the age of the person being turned into, as well as any injuries they have acquired, as Barty Crouch, Jr. needed a magical eye and wooden leg when he used the potion to turn into Alastor Moody. In addition, congenital conditions of the person will apparently be replicated, as Hermione Granger required spectacles to see clearly after turning into Harry Potter.

The potion is complicated and can go awry. For example, when Hermione brewed Polyjuice in her second year, she intended to take the form of Millicent Bulstrode, but she mistook a cat's hair for Millicent's. The resulting potion caused Hermione to partially transform into a cat. As the Polyjuice Potion cannot be used to successfully transform into an animal, Hermione's change did not reverse after an hour. She went to the hospital wing and did not recover until after the winter holidays.

Likewise, the potion cannot be used by a non-human or half-breed individual to turn into a human, as Remus Lupin informed the half-giant Rubeus Hagrid. However, it seems that individuals whose non-human ancestry is less than half can successfully use Polyjuice, as quarter-Veela witch Fleur Delacour transformed into Harry Potter in 1997. However, it is also possible Lupin meant that a person cannot transform into a half-breed using Polyjuice Potion, but half-breeds themselves can.

Search for the Heir of Slytherin


In their second year, Harry Potter, Ron Weasley, and Hermione Granger came to suspect that Draco Malfoy was the Heir of Slytherin. To investigate this, Hermione suggested the use of Polyjuice Potion to enable them to take on the form of Slytherin students and question Malfoy. Masterminding the effort, Hermione obtained the advanced potion's recipe (by getting Professor Lockhart to sign a note authorizing her to borrow the book Moste Potente Potions from the library's Restricted Section), pilfered two of the rarer ingredients from Snape's cupboards, and undertook the complex and lengthy brewing of the base Polyjuice Potion. She also directed how the trio were to acquire the final ingredients - hair from their targets - as well as clothing to complete the disguise. Ultimately, however, though Harry and Ron successfully assumed the appearances of Goyle and Crabbe respectively, Hermione's own attempt to take on the guise of Millicent Bulstrode went awry when Hermione used a cat hair that she had mistaken for Millicent's.

Barty Crouch Jr.
When Barty Crouch Jr. was sent to Azkaban for life by his father, his mother requested that her husband allow her to switch places to save their son. The switch was made with Mrs. Crouch and Barty Jr. each taking a dose of Polyjuice Potion with each other's hair. Mrs. Crouch was careful in drinking her remaining of the potion, until she died, so she could keep the prisoners fooled by maintaining her false appearance.

Between September of 1994 and June of 1995, Barty Crouch Jr. used Polyjuice Potion to take on the appearance of Alastor Moody, Hogwarts' new Defence Against the Dark Arts professor, in order to enter Harry Potter into the Triwizard Tournament as part of Lord Voldemort's plot to return to power. Throughout the year, Crouch stole the potion's ingredients from Severus Snape's cupboards, leading Snape to suspect that Harry himself was behind the theft. Crouch was eventually exposed.

Plot against Dumbledore
After Horace Slughorn showed a cauldron of the Polyjuice Potion to his first N.E.W.T. Potions class, Draco Malfoy stole some, and forced Gregory Goyle and Vincent Crabbe to use it continuously throughout the 1996–1997 school year. They would stand watch outside the Room of Requirement disguised as young girls, while Malfoy repaired a Vanishing Cabinet inside, as part of his assignment to assassinate Albus Dumbledore and let Death Eaters into Hogwarts. Draco also imperioused Madam Rosemerta and Katie Bell so that they would help kill Dumbledore.

Battle of the seven Potters
"Fourteen of us won’t be flying to Tonks’s parents. There will be seven Harry Potters moving through the skies tonight, each of them with a companion, each pair heading for a different safe house."

- Alastor Moody on the plan to move Harry to safety in 1997

The Order of the Phoenix made use of Polyjuice in 1997 in order to safely remove Harry Potter from 4 Privet Drive before his seventeenth birthday. Six people — Hermione Granger, Ron Weasley, Fleur Delacour, Fred and George Weasley, and Mundungus Fletcher — impersonated Harry in order to act as diversions when they were ambushed by Death Eaters. Soon after, Harry himself used it to disguise himself as "Barny Weasley" at Bill Weasley and Fleur Delacour's wedding.

Infiltration of the Ministry and Gringotts Break-In
The trio used Polyjuice that they stole from Moody to infiltrate the Ministry of Magic to search for Salazar Slytherin's Locket in September of 1997. Harry, Ron and Hermione disguised themselves as Albert Runcorn, Reginald Cattermole, and Mafalda Hopkirk, respectively.

The following year, Hermione used the remaining Polyjuice Potion again as part of the trio's plan to break in to Gringotts in order to retrieve Helga Hufflepuff's Cup from the Lestrange Vault. Using a strand of Bellatrix Lestrange's hair that had fallen on her sweater while Bellatrix interrogated her at Malfoy Manor, Hermione assumed her form. However, there wasn't enough, so Ron had to simply use cosmetic design to disguise himself. The effects of the potion were washed away by the Thief's Downfall at the bank.

The lack of suspicion in anyone in all these incidents leads one to the understanding that Polyjuice Potion is very uncommon. Granted, Severus Snape knew someone was stealing the ingredients from his cupboards and suspected Harry Potter, but that is more indicative of Snape's eagerness to blame Harry for anything than any actual guilt.

Behind the scenes

 * In the film adaptations of Harry Potter and the Chamber of Secrets, Harry Potter and the Deathly Hallows: Part 1, and Harry Potter and the Deathly Hallows: Part 2 Polyjuice Potion does not cause the drinker's voice to change as well as their appearance. This was most likely done to avoid confusing the audience due to the change in appearance. However, Barty Crouch Jr.'s voice does change to Moody's in Harry Potter and the Goblet of Fire (film). However, it is possible he could have just been imitating Moody's voice. It does say, however, in the Chamber of Secrets book, that Harry, Ron and Hermione's voices changed after taking it.
 * The name 'Polyjuice' probably comes from the Greek poly, meaning "many". This is supported by the fact that in the Spanish translations, it is called "multijugos," literally "multi juice."
 * In the PlayStation 2 and Xbox video game adaptations of Harry Potter and the Prisoner of Azkaban Draco Malfoy uses the potion to turn into Ron to trick Harry into following him into a trap while trying to find Sirius Black.
 * In Lego Harry Potter: Years 1-4, Polyjuice Potion is used to turn into any playable character you have unlocked (e.g. if you needed to get into the Slytherin Common Room, you could use Polyjuice to turn into Voldemort, Marcus Flint, or any other Slytherin). You cannot use the potion until the player has completed the third level of The Chamber Of Secrets, "Crabbe and Goyle." Ingrediants to make the potion, include hair, two cherries, and a green apple. The potion is found rarely throughout the main-story line, but is often found in and around Hogwarts and in Bonus Levels. You know it is a Polyjuice Cauldron, because they are the only potion's cauldron that is gold. Outside of Madam Malkin's Robes for All Occasions is one that you do not have to make. This cauldron is here, so that the player can test out characters that they have created and/or purchased.
 * In Harry Potter and the Deathly Hallows: Part 1, before the Battle over Little Whinging, Alastor Moody warns the people taking the potion that it tastes like, "goblin piss".
 * In Harry Potter and the Deathly Hallows: Part 1, Harry and Hermione do not disguise themselves with Polyjuice Potion for their trip to Godric's Hollow on 24 December, 1997.
 * After the Battle over Little Whinging, Remus Lupin mentions that Polyjuice Potion only works for humans, which is why he doesn't require half-giant Rubeus Hagrid to prove his identity. However, Fleur Delacour had just used the potion to serve as one of the decoy Potters, despite the fact she is one-quarter Veela.
 * In the films, Polyjuice Potion does not appear to have a different taste depending on the person they are changing into, as they are all depicted as tasting disgusting.

Appearances

 * Harry Potter and the Chamber of Secrets
 * Harry Potter and the Chamber of Secrets (film)
 * Harry Potter and the Chamber of Secrets (video game)
 * Harry Potter and the Prisoner of Azkaban (video game)
 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Goblet of Fire (film)
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Order of the Phoenix (film)
 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Half-Blood Prince (film)
 * Harry Potter and the Half-Blood Prince (video game)
 * Harry Potter and the Deathly Hallows
 * Harry Potter and the Deathly Hallows: Part 1
 * Harry Potter and the Deathly Hallows: Part 1 (video game)
 * Harry Potter and the Deathly Hallows: Part 2
 * The Road to Hogwarts Sweepstakes
 * Lego Harry Potter: Years 1-4

Notes and references
Polynectar