In Chapter 1 of The Witcher 2, I encountered two people dressed in merchant clothing who asked me to test a potion for them, with promises of great rewards to come in a year or two at Vizima. They were whispering cautiously between themselves and one of them shouted that the gods have no love for my kind as I approached. In spite of this, I decided to be a trusting person and took the substance. According to my inventory, it's a Critical Effects mutagen.



While I know how to use mutagens, I'm cautious to apply this one without understanding the consequences. Is this just a convenient scenario used by the game as an introduction to mutagens or will it have consequences on my character during later events?

  • 7
    Consequences of accepting unknown substances from strange men: you wake up in even stranger places with missing articles of clothing and a weird taste in your mouth.
    – Shaun
    Commented May 27, 2011 at 21:09
  • 7
    Or in a tub of ice missing a kidney...
    – Rapida
    Commented May 27, 2011 at 21:12
  • 2
    I'm fully convinced that The Witcher 2 was made just to give Gaming.SE awesome question titles.
    – Wipqozn
    Commented Jun 24, 2011 at 13:52

4 Answers 4


I'm pretty sure this is just a mutagen like all the others you find. There is no indication in the game that this one should be different. I used the mutagen and encountered no noticeable effects later.

You should know that the mutagens are permanent, so never use the standard or lower versions of the mutagens, only the greater ones (if they exist for that kind of mutagen).

  • No effects on the plot, either, I'm guessing?
    – Mana
    Commented May 28, 2011 at 23:59

I've found out this decision could affect The Witcher 3 in a bit.

witcher mutagen

  • In which way does the decision affect Witcher 3? Commented Nov 5, 2015 at 6:40
  • Don't know why this has not more upvotes. mmd actually Commented Jan 3, 2016 at 21:51

This mutagen is supposedly to give 5% more adrenaline regeneration (it's an epic). Don't use it, as it doesn't work and stops adrenaline accumulation. I had to turn back in the game when I noticed it, and I had advanced a lot!

  • 2
    Are you sure, I can't find any other information that describes this encounter with that result.
    – bwarner
    Commented Aug 22, 2011 at 11:30

I took it and it subtracted 2 intelligence, but added 3 vitality. I assume the brain trauma was due to the muscle growth, and to represent a penchant for taking illicit drugs from strangers.

  • 1
    Why did this get down voted (without a comment)? Commented Aug 22, 2011 at 11:39
  • 1
    Because it appears to be inaccurate perhaps? Commented Aug 22, 2011 at 14:42

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