What Is Epibatidine? The Rare Toxin Allegedly Linked To Alexei Navalny’s Death

Russian opposition leader Alexei Navalny was allegedly killed using epibatidine, a highly toxic neurotoxin found in certain South American poison dart frogs, according to the UK and several European allies.

Navalny died in February 2024 at the remote "Polar Wolf" penal colony in the Arctic, where he had been imprisoned after surviving a previous poisoning with Novichok nerve agent in 2020.

Russian authorities said he collapsed after a walk and attributed his death to high blood pressure linked to a chronic heart condition. His body was returned to his family eight days later. Last year, his widow, Yulia Navalnaya, said biological samples were smuggled abroad and independently examined in at least two countries.

According to the experts, the epibatidine acts on nicotinic receptors in the nervous system and is estimated to be about 200 times more potent than morphine.

In high doses, toxin can cause severe nerve overstimulation, leading to muscle twitching, paralysis, seizures, respiratory failure and death by suffocation. The toxin is extremely rare in nature and is found only in certain poison dart frog species native to Ecuador and Peru.

The Russian government, which has repeatedly denied any responsibility for Navalny's death, dismissed the latest allegations as "a Western propaganda hoax," according to the Russian state's TASS news agency.