Hermione states that they are breaking about 50 school rules making the polyjuice potion. Do we know any of the rules being broken?

  • 9
    Among other things, didn't she steal ingredients from Snape's classroom? Sep 11, 2015 at 16:09
  • 5
    Somehow I think that line may have been more conversational than calculated. Its like when you know you are going to get in trouble for something. At any given time during the series they are usually breaking at least one rule, that was never even a concern for them. I think the sheer gravity of the act weighed more than the number of technical infringements.
    – Anton
    Feb 16, 2016 at 10:15

2 Answers 2


Although it's not clear what rules Hermione was referring to, we can see what rules they actually broke:

  • Entering the restricted section of the Library and, presumably making a potion that the Potions-Master considers too advanced

Snape said it was in a book called Moste Potente Potions and it’s bound to be in the Restricted Section of the library.’

  • Lying to a teacher in order to remove said book from the library

‘Er – Professor Lockhart?’ Hermione stammered. ‘I wanted to – to get this book out of the library. Just for background reading.’

  • Having boys in the girls' lavatory

Hermione had overridden Ron’s objections by pointing out that it was the last place anyone in their right minds would go, so they were guaranteed some privacy.

  • Stealing from Snape's private stash of potion ingredients

‘D’you realise how much we’re going to have to steal, Hermione? Shredded skin of Boomslang, that’s definitely not in the students’ cupboard. What’re we going to do, break into Snape’s private stores? I don’t know if this is a good idea …’

  • Leaving a fire unattended (except for a ghost)

‘Well, as the fluxweed has got to be picked at the full moon and the lacewings have got to be stewed for twenty-one days … I’d say it’d be ready in about a month, if we can get all the ingredients.’

  • Causing an explosion in the Potions class

Harry ducked swiftly down behind his cauldron, pulled one of Fred’s Filibuster fireworks out of his pocket and gave it a quick prod with his wand. The firework began to fizz and sputter. Knowing he had only seconds, Harry straightened up, took aim, and lobbed it into the air; it landed right on target in Goyle’s cauldron.

  • Having a girl in the boy's dormitory

Harry and Ron, the only ones left in their dormitory, were woken very early by Hermione, who burst in, fully dressed and carrying presents for them both. ‘Wake up,’ she said loudly, pulling back the curtains at the window. ‘Hermione – you’re not supposed to be in here,’ said Ron, shielding his eyes against the light.

  • Drugging Crabbe and Goyle

‘How thick can you get?’ Ron whispered ecstatically, as Crabbe gleefully pointed out the cakes to Goyle and grabbed them. Grinning stupidly, they stuffed the cakes whole into their large mouths. For a moment, both of them chewed greedily, looks of triumph on their faces. Then, without the smallest change of expression, they both keeled over backwards onto the floor.

  • Stealing their shoes

They also stole their shoes, because their own were far too small for Crabbe- and Goyle-sized feet.

  • Impersonating Crabbe and Goyle (obviously)

  • Stealing clothes

‘Good. And I sneaked these spare robes out of the laundry,’ Hermione said, holding up a small sack. ‘You’ll need bigger sizes once you’re Crabbe and Goyle.’

  • Sneaking into another house's common room

‘Oh yeah – pure-blood!’ said Malfoy, not listening, and a stone door concealed in the wall slid open. Malfoy marched through it and Harry and Ron followed him.

My instinct says that doing certain spells without permission, removing dangerous books from the library, impersonating other pupils and sneaking into other houses' common rooms is probably what Hermione is driving it.

  • It is unlikely that the stolen/missing clothing would have given anyone much cause to pause, although I'm sure Draco, Crabbe and Goyle would've given Ron and Harry a few choice words, had they known. People kept taking and hiding Luna's clothes, seemingly without rebuke from any individuals of authority.
    – Xantec
    Sep 11, 2015 at 19:16
  • It is questionable whether the fire was ever left unattended, as Moaning Myrtle could've kept an eye on it.
    – Xantec
    Sep 11, 2015 at 19:17
  • 2
    @Xantec - I lit the fire, but it was attended by someone who can't do anything if it causes an accident? Hmm. Not a defence I'd like to rely on in court
    – Valorum
    Sep 11, 2015 at 19:18
  • 1
    Myrtle could've flooded the bathroom, thus extinguishing the fire. IIRC she was known to do that periodically. Worst case she could have found a teacher and told them that the bathroom was on fire.
    – Xantec
    Sep 11, 2015 at 19:20
  • 1
    @niemiro she used it in year one against snape AFAIK, during the quiditch game where harrys broom was being cursed by quirrell.harrypotter.wikia.com/wiki/Bluebell_Flames
    – Himarm
    Sep 11, 2015 at 21:51

Let's see. These are all the rule violations, misdemeanors, and felonies I can think of in the plan they used.

  • Theft of school property "they used school supplies in the potion".
  • Setting off a firework in a room which is generally full of potentially dangerous liquids and people, which could count as arson, terrorism, malicious destruction of property, assault, or attempted murder. These are all felonies and probably violate school rules.
  • Drugging a student without their knowledge. Twice. This doubles as kidnapping, since they were dragged away against their will and put in a closet. Twice.
  • Stealing clothes from another student. Twice.
  • Stealing hair from another student. 2 times.
  • Guys going into the girl's bathroom several times. If one of them were pre-op transexual, it would be okay, but this is probably a violation of school rules, since similar rules exist about the dorms. Percy actually deducted points over this matter. We don't know how many times they were in there.
  • Impersonating another student "identity theft". Two counts. A third attempted count.
  • This potion is extremely complicated and easy to screw up, which could poison someone, which probably is a violation of rules about endangering other student's lives. At least 3 counts.
  • Leaving an unattended fire, since the potion needs to stew for 21 days. Leaving a fire unattended is generally illegal.

Did I miss anything?

  • 1
    "Stealing hair"? You are joking, right? Sep 11, 2015 at 19:27
  • 5
    That's generally frowned on. Especially when one is dealing with the creepy stalkers who will steal some hair for creepy shrine/fetish reasons. It's grounds for a restraining order. Sep 11, 2015 at 19:51
  • 1
    And it's got to be even more frowned on in a place where it's actually true that you can use people's hair to cast spells on them (or, at least, about them) and everyone knows it.
    – A. B.
    May 17, 2021 at 5:38

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