The Russian opponent Alexei Navalny was murdered with a very peculiar poison, according to the United Kingdom, Sweden, France, Germany and the Netherlands: epibatidine, a toxin from poisonous frogs in Latin America. “Unfounded” accusations according to Russia, suspected on several occasions of having resorted to especially deadly poisons.

First modification: 02/16/2026 - 23:43

This is a rare poison from a frog that only lives in some Latin American countries, such as Peru. Epibatidine, a very toxic substance, would have been used to poison Alexei Navalny, the famous Russian opponent of Vladimir Putin who died in prison on February 16, 2024, exactly two years ago.

At least that is what five European countries claim after a joint investigation: “The United Kingdom, Sweden, France, Germany and the Netherlands are convinced that Alexei Navalny was poisoned with a lethal toxin,” their representatives declared on the sidelines of the Munich Conference on International Security, on Saturday, February 14.

From polonium to epibatidine

Laboratory analyzes on a European scale have made it possible to isolate traces of “a deadly toxin present in the skin of poisonous frogs in Ecuador, epibatidine” in skin samples from Alexei Navalny, the five States stated.

“We firmly reject these accusations, which are biased and not based on anything concrete,” responded Dmitri Peskov, spokesman for the Russian president.

But these conclusions and the announcement made on the occasion of the most important conference on international security have allowed the poisonous frog and its epibatidine to attract global attention.

Read alsoRussia fatally poisoned Navalny with a "rare toxin", European countries say in joint statement

This exotic poison is in addition to polonium, the radioactive substance used to poison Alexander Litvinenko in 2006, and Novichok, the nerve agent used in the attempted assassination of former double agent Sergei Skripal in 2018. In all cases, Moscow is accused of being behind these poisonings.

In the case of Alexei Navalny, "the symptoms before his death correspond to the known effects of epibatidine," highlights the independent Russian media 'Meduza'. Exposure to this poison causes muscle contractions, paralysis, seizures, slowing of the heart rate and respiratory failure, as Jill Johnson, a British toxicologist, explained to the BBC.

In the last two days, almost everything has been said in the media, including France 24, about the danger of this toxin “200 times more powerful than morphine”.

Discreet and deadly

But “why would Russia, which already had Alexei Navalny detained, have needed to resort to such an exotic toxin to eliminate this opponent?” asks Kevin Riehle, a specialist in intelligence services at Brunel University in London.

The Russian security services “could have used any other poison against Alexei Navalny, or simply let him die in prison,” agrees Luca Trenta, a researcher in International Relations at Swansea University and a specialist in assassination operations by the secret services.

From a toxicological point of view, the use of epibatidine can be justified by its effectiveness. "In the case of other, more well-known nerve agents, such as sarin or Novichok, it is possible to counteract their effects with very good medical care applied at a very early stage. But I have no idea how epibatidine poisonings are treated, and I have not seen anything conclusive about it," says Alastair Hay, a toxicologist at the University of Leeds.

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There is only one documented case of a person exposed to this poison who survived: a laboratory technician in the United States in 2010. But the story of his rescue, with the help of antihistamines, “raises many questions,” says Alastair Hay.

A substance that is difficult to counteract... and to detect. “A relatively low dose is enough for it to be fatal, which means that traces in the body are difficult to find in analyses,” explains the British toxicologist.

This is even less obvious if you don't know what to look for. And since epibatidine does not appear to have ever been used in poisoning cases before, it is not the first toxin that analysts will try to identify in the body.

This poison is also quite easy to administer: “It is known that you can be poisoned by ingesting it, by exposing yourself to it through the skin and, although it is less documented, it is probably a poison that can act when inhaled,” details Alastair Hay.

Navalny, a guinea pig?

All these aspects are not enough to justify the use of epibatidine against an opponent who was already in poor health and behind bars in Russia, believes Kevin Riehle. “The only reason I can think of, and it is quite monstrous, would be that Alexei Navalny served as a guinea pig for this poison,” he says.

In fact, this toxin "has been known for decades by scientists who have tried to use it as an analgesic. Today, the substance can be reproduced in the laboratory," confirms Alastair Hay. “The development of this weapon is not difficult,” but its effectiveness still needs to be ensured, Luca Trenta acknowledges.

For Moscow, it can also be a way of remembering that “its laboratories, which have been working on the development of poisons for decades, are still capable of developing new complex and effective toxins,” emphasizes Mark Galeotti, a specialist in security issues in Russia and director of the consulting firm Mayak Intelligence.

According to this expert, the use of epibatidine serves to create "a constructive ambiguity." “On the one hand, the Russian authorities could hope that the poisoning would go unnoticed, but on the other hand, if it was discovered, it would be better to use a rare and exotic poison,” says Mark Galeotti. This way of shocking public opinion with images of deadly frogs and poison coming from far away “allows the creation of a narrative that demonstrates how far the Kremlin is willing to go to silence its critics,” says this specialist.

Finally, “the use of poison is also a matter of revenge against opponents of Russian power,” says Luca Trenta. And to turn the death of an obstacle of Alexei Navalny's caliber into a resounding example, what better way than with an exotic, unprecedented and particularly virulent poison?

This article is adapted from its French version

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