Several European countries, including the United Kingdom, claim that Russian opposition leader Alexei Navalny was killed using a rare and highly potent toxin derived from the skin of a small red frog found in parts of South America.

According to the UK Foreign Office, forensic tests conducted on Navalny’s body reportedly detected traces of epibatidine, a powerful chemical compound associated with the Anthony’s poison arrow frog — a species native to Ecuador and Peru.

Epibatidine can be extracted directly from the frog’s skin or synthesized in a laboratory. British authorities argue that the substance is extremely rare and difficult to obtain, suggesting that such an operation would have required the involvement of the Russian state.

They further allege that Navalny may have been poisoned while in detention, insisting that Moscow had the “means, motive, and opportunity” to deploy such a lethal agent.

The Kremlin has strongly denied the accusations. Presidential spokesperson Maria Zakharova dismissed the claims as “fabrications” designed to distract and mislead the public. Russian officials maintain that Navalny died of natural causes.

Russia’s prison service reported that the 47-year-old opposition figure died on Monday, February 16, 2026, at a penal colony in the Arctic region where he was serving his sentence.

Authorities stated that he began feeling unwell after a walk, lost consciousness, and collapsed. Emergency responders and medical personnel were unable to revive him.

What Is Epibatidine?

Epibatidine is a naturally occurring toxin found in certain species of poison dart frogs native to Ecuador and Peru.

Toxicology expert, Jill Johnson, told the BBC that the compound is roughly 200 times more potent than morphine, the opioid derived from opium and commonly used in medicine for pain relief.

Because of its extreme potency and high toxicity, epibatidine has never been approved for medical use.

Once inside the human body, the toxin interferes with nerve receptors responsible for transmitting signals between nerves and muscles. This disruption can cause severe neurological damage, muscle paralysis, slowed heart function, and respiratory failure — ultimately leading to death.

Alastair Hay, a toxicology specialist at the University of Leeds, explained that exposure to epibatidine can quickly result in respiratory collapse.

“Anyone exposed to this substance would die from lack of oxygen,” he noted, adding that the presence of the toxin in a person’s bloodstream would strongly indicate deliberate administration.