Berserkers were infamous viking warriors who fought in a trance-like fury, and were said to be stronger and more dangerous than other warriors. The cause for their intoxicated mindstate has long been speculated, but without a definite answer. Ethnobotanist Karsten Fatur from the university of Ljbuljana in Slovenia believes, based on ancient descriptions, that the warriors may have been intoxicated with henbane.
Hyoscyamus niger Hyoscyamus niger, or henbane is a poisonous plant indignous to Europe. It has been found in various viking graves and other archaeological sites and is known to cause hallucinations and restlessness, but also aggression in people who consume it. It has seen uses as an anaesthetic and as a psychoactive substance, even used by oracles in ancient Greece.
Although speculative, Fatur believes henbane is more likely than other theorised substances, such as fly agaric mushroom, as it explains the various effects better, associated with the warriors. Despite causing hallucinations, fly agaric is not known to cause aggression. It also doesn’t cause headaches and blurry vision, which were reported with the berserkers. Henbane does.