I was thinking about an answer to an older question about HBP, and it dawned on me: merely getting a confirmation that there were 7 Horcruxes was important but hardly the most critical endeavour of the entire War (actually getting and destroying Horcruxs was). So why was Felix only used once, in that specific case?

We know Felix Felicis is hard to make, but we also know that it's possible to make. Slughorn can, for example.

Why doesn't either side in the War pay someone like Slughorn to make Felix for them?

A critical mission - like Dumbledore going to Gaunt shack, etc... - would be well worth the price no matter how expensive the potion is. And Slug likes his creature comforts, so he would be more than willing to put in the effort if paid well.

Hell, it is not so super priceless and rare and hard to make that Slug wasn't willing to give one as a prize to one of his students!

The obvious reasons don't seem to work:

  • Money is no object. Either side has wealthy wizards who can pay (Malfoy, Harry, Longbottom). For that matter, even if Dumbledore is not himself wealthy, he's a great enough wizard that he can trade some magical favors/inventions to Slughorn or another potion maker of his caliber.

  • Felix is not some deeply held secret. It's listed as prohibited aid for sporting events.

  • The fact that at the very least Slughorn is an advanced potion maker who can do it is also not exactly a secret - he told Harry's class he can make it, and probably told prior students of his (Tom Riddle included).

  • "... highly toxic in large quantities" answer from Slughorn from HBP. But there's a difference between frequent use/large quantities; and strategic rare use for critical missions (e.g. retrieving/destroying Horcruxes). Both Dumbledore and Voldemort possess enough willpower to enforce that (and DEs wouldn't even care too much in the first place)

I would strongly prefer canon based or JKR answers.

  • 4
    As a side note, surely Snape could make Felix? I don't know of any canon proof that he could, but he was a Potions professor, like Slughorn. Sep 10, 2012 at 17:44
  • 6
    Indeed, he was a potions professor of unusual skill and competence. It's hard to imagine the half-blood prince being unable to handle a potion that Slughorn could.
    – Tynam
    Sep 10, 2012 at 17:53
  • 5
    Related: scifi.stackexchange.com/questions/11633/… Sep 10, 2012 at 17:54
  • 1
    @JackBNimble - Yeah, I remember that one. But none of the answers really addressed my question (Keith's was the best but it didn't address spare use for critical things). And my own answer wasn't as well based on canon as it should have to answer this one. Sep 10, 2012 at 17:58
  • 5
    Another good time use it would have been when Harry left the Dursley's house for the last time.
    – Xantec
    Sep 10, 2012 at 18:15

9 Answers 9


Well, there's always the consideration that Voldemort's side did use Felix Felicis at times. Canon doesn't indicate otherwise (and I realize that the absence of information does not a fact make). I think it's okay to consider the possibility that the Death Eaters engaged any and all methods of magic that might have given them an advantage, and it's fair to say that the Death Eaters had their fair share of successes and triumphs in their endeavors.

Felix Felicis is a tricky potion to brew and probably wouldn't be the best choice for mass production and consumption. In chapter 24 of Half-Blood Prince, Sectumsempra, Harry reads the instructions for Felix Felicis (which is indeed in the sixth year book Advanced Potion-Making, so there's no question that Snape would have known how to brew it) and notes that not only are the ingredients complex, but that it takes six months to brew Felix Felicis. War does not wait for a potion to finish brewing. Keeping Felix Felicis in supply, on demand, would have been incredibly difficult, if not impossible.

You already mentioned that Felix Felicis is toxic in high quantities. In Half-Blood Prince, chapter 9, The Half-Blood Prince, Slughorn mentions quite a few things about Felix Felicis. It's disastrous when brewed improperly. Slughorn doesn't mention how a potioneer would be able to tell if the potion wasn't brewed correctly, but if it's one of those situations where one wouldn't know until they take the potion, Felix Felicis would then be an incredibly risky potion to dole out to the troops on a regular basis.

Slughorn says Felix Felicis should be taken only sparingly and on occasion. Taking it too often causes giddiness, recklessness, and a false sense of overconfidence. He also says that this potion works from "dawn to dusk" -- what about any combat that takes place after dusk?¹

Naturally, Felix Felicis is an inherently abusable potion for those seeking the wonderful feelings of unstoppable confidence and accomplishment. In this regard, it would be at high risk for being regularly stolen by individuals looking to experience those particular feelings again and again.

Also, I think Felix Felicis gives the taker what they need, not what they want -- an important distinction. Harry needed Slughorn's memory of Tom Riddle. So bringing the topic back to a wartime situation, one person might want to kill another during a duel, but what they need is just to escape the situation alive, and Felix Felicis might facilitate escaping alive, but not the desire to take another's life.

¹This is actually contradicted in chapter 22 of Half-Blood Prince, After the Burial.

  • 32
    I'm pretty sure "dawn to dusk" was intended as a timespan, i.e. ~15 hours, not absolute bounds.
    – Kevin
    Sep 11, 2012 at 1:36
  • 5
    And technically, the potion did play a nontrivial part in his getting together with Ginny, as it incited her and (I believe) Dean's breakup.
    – Kevin
    Sep 11, 2012 at 1:39
  • 3
    @Slytherincess - sorry, 2 quibbles: (1) I am asking specifically about select high impact missions. None of the paragraphs related to high-volume use apply... Sep 11, 2012 at 3:01
  • 11
    ... (2) I think that the idea of "what you need vs. what you want" is contradicted by canon. Never mind Ginny's breakup, the potion is prohibited for sports games. Nobody ever needs to win a sports game. They may want to, but surely they need to a lot less than a DA member to kill a DE (who, if not neutralized, will go on murdering wizards and muggles alike). Sep 11, 2012 at 3:03
  • 20
    @Slytherincess: "Getting through the portrait hole was simple; as he approached it, Ginny and Dean came through it and Harry was able to slip between them. As he did so, he brushed accidentally against Ginny. 'Don't push me, please, Dean,' she said, sounding annoyed. 'You're always doing that, I can get through perfectly well on my own...' // ... // 'Well, it was a bad night for romance all round. Ginny and Dean split up too, Harry.' ... 'How come?' 'Oh, something really silly ... she said he was always trying to help her through the portrait hole, like she couldn't climb in herself."
    – Kevin
    Sep 15, 2012 at 0:40

Well we do not know the Ingredients for Felix Felicis because they were never mentioned in the book, but we know that Slughorn was on the run and brewing Felix (probably in a safe house because it takes 6 months). When he returned to Hogwarts (at the beginning of book 6) he did not needed anymore as he was no longer on the run. He probably kept some for himself and may have used it at the battle of Hogwarts in book 7.

That means in the whole seven books Felix was just brewed one time (that we know of). I believe because the Ingredients have to be really, really rare (you must have "Luck" finding them), very pricey (Gold is said to give Luck for example and Felix looks like molten gold) or both. It could also need an ingredient from a rare magical animal that is generally very lucky and because of this difficult to get (because the animal would seize every oportunity to escape or to hide). We know Slughorn is very well connected due to his always growing network of ex-students. He could ask a few favours back, one ingredient a time, until he has everything he needs for the potion.

Also we do not know how long it stays fresh.


It only helps in cases where all needed to succeed is more luck.

Felix Felicis had limitations - it increases luck, but doesn’t increase skill or ability. Hermione tells Harry that luck would only get him so far and Felix Felicis wouldn’t get him through a powerful enchantment. It’s just a luck potion, not a miracle, and it can’t make someone do anything they’re incapable of doing with just more luck and confidence. It can also illuminate the best path to take, but it wouldn’t finish what needs to be done, especially because it’d wear off before the really important parts - if it reveals the Horcruxes exist, for example, it’d wear off before they’re found.

“I think I’m going to take another swig of Felix,’ said Harry, ‘and have a go at the Room of Requirement again.’

‘That would be a complete waste of potion,’ said Hermione flatly, putting down the copy of Spellman’s Syllabary she had just taken out of her bag. ‘Luck can only get you so far, Harry. The situation with Slughorn was different; you always had the ability to persuade him, you just needed to tweak the circumstances a bit. Luck isn’t enough to get you through a powerful enchantment, though.”
- Harry Potter and the Half-Blood Prince, Chapter 24 (Sectumsempra)

The main problems that both sides faced weren’t necessarily solvable with luck. The Dark Lord needed to get past Harry’s various plot armor magical protections (like the sacrifice in his blood, the twin cores, and his being tied to life while the Dark Lord lived). Harry, and Dumbledore first needed to find all the Horcruxes before the Dark Lord could possibly be killed. We don’t know all the details of the Death Eaters’ strategy, so it’s possible they may have taken it at some point, but even if they did (which isn’t anyway certain) it most likely wouldn’t help the Harry situation.

It’s also important to note that the only one who we know of that used Felix Felicis in this sort of way (to help him get a memory and to give Dumbledore’s Army) was Harry, who would very likely be less knowledgeable about it than either Dumbledore or the Dark Lord. They’d likely know more about its effects than him and could better decide if to use it.

It may also have a negative effect on luck while wearing off.

In addition, it’s possible it might cause luck to be worse for a bit when it wears off. Harry’s luck seems to change as it wears off - he encounters Peeves and the Fat Lady lies to him about the password changing because she was annoyed with him. This isn’t a big deal here, if it is worse luck caused by the potion, but could be disastrous if it wears off during a critical mission vital to success.

“Harry could feel the Felix Felicis wearing off as he crept back into the castle. The front door had remained unlocked for him, but on the third floor he met Peeves and only narrowly avoided detection by diving sideways through one of his short cuts. By the time he got up to the portrait of the Fat Lady and pulled off his Invisibility Cloak, he was not surprised to find her in a most unhelpful mood.”
- Harry Potter and the Half-Blood Prince, Chapter 23 (Horcruxes)

In Harry’s case, he didn’t have much that could go disastrously wrong. If the Felix Felicis causes worse luck for a bit when it wears off, then if it wears off in the middle of something important, it could cause something bad to happen, and possibly could even cause it to go worse than it would have without any Felix Felicis. We know it’s dangerous to take too much, so they can’t just have more. Especially if this is an effect, it mightn’t be worth it using Felix Felicis for a bit of extra luck.


If both sides did use it, technically it would have been a stalemate of some sort. Both sides could easily make it as the Half-Blood Prince, Harry and Slughorn could. Which is probably why no side did use it and resorted to other tactics. And really the war was only ever between two people and goes back to the curse and the phrase 'the boy who lived'.


They may have not used it when looking for Horcruxes because they knew Voldemort would have enchantment barriers. For example, when stealing Hufflepuff's Cup from Bellatrix Lestrange's vault they had to cross under a waterfall that washed away all enchantments. Their Polyjuice potions washed away, as well as the Imperius Curse they had used on the Goblin, so it would probably have disabled Felix too right? Or when Dumbledore and Harry were trying to get Slytherin's Locket (the one that ended up being only a replica) out of the cave. Would Felix have actually been able to help Dumbledore drink the cursed water from the bowl at all? It's questionable. Harry did destroy Tom's diary before he learned about Felix though, so that's a definite answer for why he didn't use it then. It could have helped with finding the diadem I suppose, or with Dumbledore trying to destroy the ring, but they already realized what they had to do after Harry took Felix to pull the truth out of Slughorn, I guess. After all it did lead them to finding out what they had to accomplish/destroy to defeat Voldemort for good.


The Baddies

In the case of the baddies I think there are two specific reasons why they may not have bothered with Felix Felicis.

The first might be a certain hubris. It's impossible to examine each Death Eater individually, but Tom Riddle in particular was very arrogant and very confident in his abilities.

'I fashioned myself a new name, a name I knew wizards everywhere would one day fear to speak, when I had become the greatest sorcerer in the world!'

Harry Potter and the Chamber of Secrets - p.231 - Bloomsbury - Chapter 17, The Heir of Slytherin

Consider also the supreme confidence Bellatrix displays in herself in her final fight:

'What will happen to your children when I've killed you?' taunted Bellatrix, as mad as her master, capering as Molly's curses danced around her. 'When Mummy's gone the same way as Freddie?'


Bellatrix's gloating smile froze [...]

Harry Potter and the Deathly Hallows - p.590 - Bloomsbury - Chapter 36, The Flaw in the Plan

I always got an impression of great pride from the higher-ups among the Death Eaters, possibly something that their Pure-Blood supremacism contributed to. It displays a certain humility - even a lack of faith in oneself - to depend on luck.

This is a minor point though. I think the major point is the Death Eaters, and particularly Voldemort, believe in Dark Magic.

'The old argument,' he said softly. 'But nothing I have seen in the world has supported your famous pronouncements that love is more powerful than my kind of magic, Dumbledore.'

Harry Potter and the Half-Blood Prince - p.415 - Bloomsbury - Chapter 20, Lord Voldemort's Request

This, I think, is very important. Don't you think lucky potion is a bit friendly? It may very well be amoral, but it's not poison and venom and hatred and fury. It's a bit well-meaning. A bit soft and fluffy. A bit nice. It may not be love. It may not be Dumbledore's kind of magic. But it's not really Voldemort's kind of magic.

The Goodies

Bellatrix beat me to one of the juicier quotes, as is her nature :P but permit to restate the point in combination with another, for I think both are needed to make the case.

Consider these two pronouncements together. First Hermione:

'Luck can only get you so far, Harry. The situation with Slughorn was different; you always had the ability to persuade him, you just needed to tweak the circumstances a bit. Luck isn’t enough to get you through a powerful enchantment, though.'

Harry Potter and the Half-Blood Prince - p.484 - Bloomsbury - Chapter 24, Sectumsempra

And, second, Slughorn:

'Because if taken in excess, it causes giddiness, recklessness and dangerous overconfidence,' said Slughorn. 'Too much of a good thing, you know ... highly toxic in large quantities. But taken sparingly, and very occasionally ...'


'Now, I must give you warning that Felix Felicis is a banned substance in organised competitions ... sporting events, for instance, examinations or elections. So the winner is to use it on an ordinary day only ... and watch how that ordinary day becomes extraordinary!'

Harry Potter and the Half-Blood Prince - p.178 - Bloomsbury - Chapter 9, The Half-Blood Prince

And this I think is the point of it. The wisdom within the wizarding world - the kind of thing surely someone like Dumbledore or McGonagall would ascribe to - is that Felix Felicis works best on an ordinary day. It works best at making something ordinary extraordinary.

Consider, luck cannot give you powers you don't already have. What it's good at is giving you confidence, lighting your path, making things work out, letting you run into the right people, making sure you don't face a locked door, helping your confidence, helping you make that save by a few millimetres instead of missing it by a few. It's a boost.

Now, having said that, we do see that the DA did use it in a battle situation and it does seem to have helped keep them alive. (However, with all such things as hand-wavey as "luck", one has to question just how lucky Ginny got that night given how her brother was brutally savaged by a werewolf).

'Harry, if we hadn't had your Felix potion, I think we'd all have been killed, but everything seemed to just miss us -'

Harry Potter and the Half-Blood Prince - p.571 - Bloomsbury - Chapter 29, The Phoenix Lament

Nevertheless, wisdom suggests great caution. As I say, liquid luck cannot give you additional powers. Now ask yourself whether it is really such a good idea for the person who believes they cannot be hit to stride confidently into battle against a stronger opposition. Who knows what kinds of horrible situations they might walk brazenly into, lacking precisely the kind of caution and fear that they might need. Of course, Felix should stop them, or put something in their path, perhaps, make sure that door is locked this time. But I think the wise path is to study and improve and better yourself so that you aren't reliant upon lucky potion, perhaps especially for something so important as a big mission. The dangers of overconfidence mixing with incompetence are ghastly and the risks of the potion running out when you're still in the mess that the lucky potion had been helping you survive are worrisome.


Other answers have touched on this, but for everyone, I think the fog of war makes having Felix around when you need it quite difficult practically too. On the Death Eater side, I think it would be hard for anyone but Voldemort to know when the next big operation is gonna be sufficiently far in advance. Dumbledore too wouldn't have known precisely when he was gonna make his next major breakthrough. Now we know from the books that Harry's phial of Felix lasts much of the school year, so it can't perish that quickly, but if we allow ourselves to assume it has a best before date, it must be tricky to ensure it's there when you need it. And what do you do when you've taken it all?

Moreover, what if it turns out that, despite (or maybe because of) your luck, this operation didn't quite turn out to be the big deal you expected. How do you know in advance whether this is the big one? And, with that in mind, how do you stop yourself depending on it? How do you know in advance whether this isn't the big one? How do you stop yourself wasting it. What if you don't take the Felix and then, since you haven't had your lucky potion, you wind up in a really big mess where this time you really do need the lucky potion. I suppose you could carry it around constantly, but it might be a bit late when you're already magically bound and gagged and really in need of a stroke of luck.


I believe that Felix is a drug. It does not provide you with any "luck", it just makes you more confident and relaxed, so your endeavors have a higher chance of succeeding. So basically a placebo. Even Ron got that effect in his quidditch match, even though Harry did not put any Felix into his cup. The whole effect is just a placebo and wizards believing it.

Some coincidences (like Ginny's breakup) support the myth of Felix, but that could well be just a survivorship bias.

Furthermore, there is strong evidence that Felix is a drug. "Taking it too often causes giddiness, recklessness, and a false sense of overconfidence" "higly toxic in large quantities" Even in the movie adaptation Harry acts like on drugs when under the influence of Felix. Slughorn is no stranger to stuff like that "but only for academical purposes, right?" yeah, right.

I believe that Dumbledore and Voldemort are aware of the true nature of Felix, so they don't pay attention to it, since once you are aware of the placebo effect, it loses the effect. There is very little direct canonical evidence supporting my claims, but it's a children's book after all, JKR cannot admit it directly. But the placebo effect is strong. Harry does not win any lottery, he just goes with his gut, feels confident, gets drunk with Slughorn and gets the information from him.

  • 2
    Is a potion not always considered a drug given as it affects your body on some level?
    – Edlothiad
    Dec 10, 2017 at 13:40
  • +Edlothiad - kind of, yeah, but that was my point, that Felix affects your body (mind, reactions, behaviour,..), it does not affect 'the outside events happening to you' Dec 10, 2017 at 14:11

In the movie, Harry Potter and the Deathly Hallows – Part 2, it looks like Slughorn does. Right as he's walking down the steps of the castle in the scene where the statues jump off the wall and march out. You see him take a swig of something. I mean... it could be something else but the container seems to be curiously small like even smaller than a tiny flask.

This happens at around 1:22 in the following clip:

  • 1
    I've edited in the clip of what I believe you are talking about. Could you also edit to explain why you think this is Felix Felicis or is this based solely on the fact that the bottle is quite small?
    – TheLethalCarrot
    Sep 21, 2018 at 8:36

Because the effects of the potion would have appeared dangerous and unhelpful.

Although this question cannot be answered from canon, it can be answered from pure logic.

(My answer only addresses why both sides did not use Felix Felicis for the ultimate goal (killing Harry or Voldemort). It does not address the use for side missions.)

Why Didnt The Order Of the Phoenix use Felix Felicis to kill Voldemort?:

The only way Voldemort could have been killed was if Harry died as well, as Harry was the eighth Horcrux. Thus, if one was using the potion to specifically kill Voldemort, the potion most likely would have told them to go after the most obvious and easy-to-kill Horcrux, Harry. Therefore it stands to reason that Dumbledore forbade the use of liquid luck to protect his most valuable weapon.

Another possibility is that since the Order of the Phoenix did not know of the existence of the Horcruxes, when one of the members consumed the Felix Felicis and found the potion directing him to Harry, he automatically assumed that the potion was tainted/evil and thus could not be used.

Why didn't Voldemort use the Felix Felicis to kill Harry?

The logic by the Order applies here too. Voldemort could not kill Harry as long as Harry's blood was in his veins. Thus, when Voldemort took the potion to kill Harry, he was surprised to find the potion directing him to kill himself. Therefore, he automatically assumed A) that the potion was tainted and could not be used or B) that any Death Eater that consumed the potion would also be directed to kill Voldemort (although this is not true as only Voldemort was unable to kill Harry but anyone else could and thus the potion would help them, Voldemort had no way of knowing this) and therefore forbade the use of Felix Felicis.

While this answers only the primary goals, perhaps we can extrapolate and say that once the sides realized the potion could not be used for the primary goals, they assumed the problem was in the potion itself and thus forbade its use for all purposes.

  • No problem with the downvote, but can you explain the reason? I believe my answer was well reasoned.
    – TheAsh
    Sep 11, 2017 at 21:56
  • I think it's because you really misinterpret the effect of the potion. It does increase one's luck, it does not paint target marks on people whose death might in some way beneficial to oneself. If anything, the potion would cause an accidental death, with noone any wiser about why it happened or that Felix was even involved.
    – Annatar
    Dec 11, 2017 at 10:04

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