The Berserker State and Amanita muscaria

A battle rages in dark spruce forests of Scandinavia. The clashing of sword against shield rings through the forest. Suddenly, charging through the trees, howling with rage, comes a living nightmare in the form of both man and beast. A Viking berserker yielding an axe and shield, covered in furs yet bare of armor, charges with a blind rage towards the enemy. The other Vikings retreat, knowing better than to get in the way, as those in the berserker state no longer distinguish between friend and foe. 

Legend has it that Viking berserkers – warriors whose exact identity have become blurred with time – consumed Amanita muscaria to enter this “berserker state.” Supposedly, consuming this fungi would drive them into a blind rage, making them extreme warriors that were numb to pain and would kill everyone in their path. Though berserkers themselves (870-1030 CE) and the so-called berserker state do seem to be well documented, there is doubt around the truth behind what caused the berserker state, and we are pretty sure that A. muscaria is not the right candidate. 

Symptoms of the berserker state 

Records of the berserker state talk about individuals being sent into a trance-like state accompanied by some of the following symptoms: 

  • Shivering 
  • Chattering of the teeth
  • Biting of their shields
  • Body chills 
  • Swollen face
  • Howling like animals 
  • Hot headedness and even rage
  • Reduced perception of pain 
  • Recklessness, no fear of death
  • Inability to distinguish between the enemy and those on their side

There are also notes about how these berserkers would react following this berserker state. They were said to have multiple “down days,” where they were extremely weak both physically and mentally.  

Currently, potential candidates for inducing the berserker state are Amanita muscaria, mental illness, alcohol, ergotism, among others, and a bit more recently, henbane (Hyoscyamus niger). One of the more widely accepted theories for the inducer of this state is A. muscaria, most likely originating from the writings of Ödmann in 1784. However, on further inspection, this mushroom does not make for a great candidate. To understand why, let’s start with some possible negative side effects of consuming this mushroom. 

Potentially harmful symptoms of consuming Amanita muscaria 

Amanita muscaria, AKA the fly agaric, is a really fascinating fungi with the potential for medicinal and spiritual use in both macro dosing rituals and micro dosing, however, when consumed incorrectly, can have some negative impacts, such as: 

  • Nausea
  • Vomiting 
  • Diarrhea
  • Dizziness
  • Dilated pupils
  • Hyperthermia 
  • Intense sweating 
  • Reddening of the face
  • Excessive salivation 
  • Twitching/trembling
  • Hallucinations 
  • Delirium
  • Seizures
  • Sleep
  • Coma
  • Rarely death (2-5% of cases
  • Very few reports of aggression (and not immediately after consumption

Now, at first this seems like a lot, but have you ever listened to the end of a commercial for a new prescription drug? The list isn’t much worse. Besides that, you will notice that these don’t really line up with the berserker state. Though hallucinations and salivation could almost fit the bill, the negative side effects surely wouldn’t help you do into battle, and instead of chills, it causes fever.

Additionally, these symptoms are primarily caused by ibotenic acid, which is only one of the key compounds in the mushroom.  And when prepared properly, the fly agaric will no longer have harmful amounts of ibotenic acid, but instead musicol. This is the compound that is also considered hallucinogenic, but also has many positive effects, with evidence that it may be the solution to many ailments. With this in mind, the fly agaric does not seem like a good candidate for inducing a cold, murderous rage, and if you talk to those who have tried it, they will tell you the same. 

What our expert source says 

Amanita Dreamer is an incredible source for knowledge on A. muscaria, and when we asked her about the legend of berserkers and Amanita, she also said that is doesn’t make any sense to her. 

She told us how when taking the fly agaric you feel warm, focused, energized, calm, and peaceful. In her time guiding people through rituals she has not seen aggression and violence in people, really the opposite. Furthermore, too much ibotenic acid, which is the harmful upper found in A. muscaria, will cause the body to reject the mushrooms before having any major effects. That statement is backed up here, where symptoms of hallucination happen almost an hour and a half after symptoms of nausea, vomiting, and diarrhea. In other words, berserkers would be a bit too busy having their body reject this compound to be in battle. 

You can watch the video to see what else she had to say: 


All in all, we find that Amanita muscaria does not make a convincing candidate for the substance behind the berserker state. First off, this fungi, when used properly, can actually be a really positive thing for those who use it. Furthermore, even the negative symptoms of eating the mushroom raw do not align with the records of “going berserk”.  Though we may never know, we think that the plant henbane may be a much better hypothesis. We will explore this in a future video, but for now you can check out this paper that breaks that idea down. 

About The Author
Kirstynn Joseph

Kirstynn Joseph

Kirstynn is an Ecologist and Science Communicator with a passion for nature, writing, science, and conservation. She was born in Yukon Territory, and is currently living in Ecuador, where she is working on various projects and exploring as much as she can before she figures out the next big adventure. For now, her main goal is to share the wonders of our big mysterious world with as many people as she can.