Alexey Navalny, prominent critic of Russian President Vladimir Putin, was poisoned, doctor insists The opposition leader was returned to jail on Monday after being hospitalized.

A personal doctor for Russia’s most prominent opposition activist, Alexey Navalny, insists he was deliberately poisoned with a “chemical agent” after he was hospitalized with a sudden skin illness he contracted while in a Moscow jail.

Navalny was taken to the hospital from jail on Sunday with what authorities said was a “severe allergic reaction.” His face and eyes were heavily swollen and much of his upper body was covered with a rash, according to his long-time eye-doctor, Anastasia Vasilyeva. The sudden illness quickly set off fears among his supporters that the Kremlin critic might have been poisoned.

Navalny was returned to jail on Monday following treatment after doctors at the hospital deemed him well enough to leave. Navalny is serving a 30-day jail sentence after he was arrested on charges of organizing an unauthorized demonstration ahead of an opposition protest last Saturday that saw a heavy police crackdown.

But his doctor, Vasilyeva, speaking to reporters outside the hospital, condemned that decision and said she had no doubts he had been poisoned, dismissing suggestions his illness might have resulted from an allergy.

“What happened to Alexey was a toxic reaction to an unknown chemical agent,” Vasilyeva said. "Alexey has had negative allergy tests for his whole life. He is in principle not allergic. At all."

Vasilyeva said the swelling on Navalny's face had gone down considerably after he was given steroids overnight. Based on that, the hospital had already declared him fit enough to be sent back to jail over Vasilyeva’s strong objections.

“They haven’t even done basic tests. And that speaks about how clearly they have sent him back to the detention center on directions from above,” Vasilyeva told reporters.

Vasilyeva said doctors had officially diagnosed Navalny with “contact dermatitis,” a common skin rash caused by contact with an irritant. She said the diagnosis proved that the 43-year-old had been in contact with some kind of chemical substance since Navalny has no allergies and had not used any new products while in jail. She accused authorities of deliberately concealing what might have caused it.

“What kind of chemical agent prompted the contact dermatitis? she said. “What was the toxic agent? Nobody knows, and mostly importantly nobody wants to know. That's the issue.”

Elena Sibikina, head of the internal medicine department at Moscow’s City Clinical Hospital 64, confirmed to reporters Navalny had been declared healthy enough to leave hospital after treatment. She refused to comment on what had caused Navalny's illness, saying she was prevented by confidentiality rules.

In a video posted by Vasilyeva on her Facebook page Monday, Navalny could be seen walking out of the hospital ward with guards, looking slightly puffy in the face and tired.

The fears that Navalny could have been poisoned emerged quickly because there is now a long list of Kremlin opponents who have suffered mysterious poisonings over the years: from pro-democracy activists to the former Russian intelligence agent, Sergey Skripal almost killed with a nerve agent in the UK in 2018. Last year, Peter Verzilov, a well-known activist from the protest group Pussy Riot, was hospitalized in a critical condition with what doctors said was almost certainly poisoning.

But while Vasilyeva said the contact dermatitis must have been caused by a chemical, in reality it can be provoked by many things, from common allergens to jewelry and plants. When Navalny was first hospitalized, one of his top lieutenants, Leonid Volkov, said he believed it was more likely the result of unsanitary conditions in the Moscow jail than poisoning. Volkov on Twitter wrote he had been in the same jail cell where Navalny was being kept during a recent 28-day detention and had come out with the same skin rash.

Navalny himself later on Monday published a post on his blog describing what had happened to him and suggesting he thought he may well have been poisoned. He noted he had never had an allergic reaction before and that he had spent many months in similar jails previously and had even been kept on the same cot in the same cell during another a short detention two weeks ago. All of his bedding was brought from home.

He said he first felt unwell on Saturday, when his cellmates notice his neck was red. He then woke up in the middle of the night, with his head and neck burning and feeling like they had been "rubbed with fibre-glass". By Sunday, he said his eyelids were the "size of ping-pong balls."

Navalny wrote he allowed there was chance he had suffered a strange allergic reaction but said he thought there was a way to check.

"I think there is simple way to decide this: Did some people come into my cell other than the staff at the detention center?" Navalny wrote. He said he ruled out the guards there because they were "more shocked" by his appearance than he was and wrote his lawyers would formally request the security camera footage showing his cell.

Given that it was still unclear what had caused Navalny's skin reaction, Vasilyeva said it was wrong and dangerous to send him back to jail. She said the hospital was now carrying out toxicology tests.

An eye-doctor and a supporter of Navalny, Vasilyeva has treated Navalny since he almost lost his right eye after a pro-Kremlin activist threw disinfectant in his face. Vasilyeva said there was serious concern the new illness could now threaten his sight if he should suffer a second reaction back in jail.

A lawyer-turned-anti-corruption activist, Navalny has become the Kremlin's most troublesome political opponent, building a sizeable following among the country's youth and recently encouraging a series of unusually large street protests. He has previously been harassed and beaten up by pro-Kremlin activists.

Navalny's sickness comes at a tense time for the opposition. Police raided the homes of key activists before Saturday's protest and ended up arresting over 1,300 people on the day of the demonstration, violently clubbing some.

The protest was called by Navalny and other activists to demand that authorities allow opposition candidates take part in Moscow's city council election in September, after several were barred from the ballot. The move has outraged Moscow's liberal society that view it as a sign the Kremlin will no longer tolerate even low-level legal political opposition. Police have since arrested and searched the homes of several of the candidates, who are also some of the country's best-known opposition activists, among them the politicians Ilya Yashin and Dmitry Gudkov and key Navalny ally Lyubov Sobol.

The opposition have called for a new protest in Moscow on August 3.