EXPERTS have warned people to stay clear of an anti-malarial drug Donald Trump said he was taking – saying it can be lethal.

Professor Simon Gibbons issued the red light after the US President announced he was taking hydroxychloroquine to stop him getting Covid-19.

"You'd be surprised at how many people are taking it, especially the frontline workers before you catch it, the frontline workers, many, many are taking it," Trump told reporters. "I happen to be taking it."

Asked what was his evidence of hydroxychloroquine's positive benefits, Trump told the press briefing yesterday: "Here's my evidence: I get a lot of positive calls about it."

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Gibbons said: "This drug in overdose can cause severe cardio-toxicity leading to death. My concern is that members of the general public may be tempted to take this drug in large doses, which is very dangerous. They must NOT do so."

The head of the University of East Anglia's School of Pharmacy added: "Hydroxychloroquine is not on 'script' to treat Covid-19 infections. It is a synthetic antimalarial based on quinine from the bark of the Cinchona tree from South America. An infusion of the bark was used to treat fevers, mostly caused by malaria. The bark was called 'Jesuit' bark after the priests who recognised its use in the 16th century.

"As there is a paucity of data for the use of hydroxychloroquine as an antiviral, it should not be taken by the general public."

The US government has warned that the drug should only be administered for Covid-19 in a hospital or research setting due to potentially fatal side effects.

Earlier today US House Speaker Nancy Pelosi has led a chorus of surprise and alarm after Trump's revelation.

"He’s our president, and I would rather he not be taking something that has not been approved by the scientists, especially in his age group and his, shall we say, weight group ... morbidly obese, they say,” she said.

Senate Democratic leader Chuck Schumer called Trump’s remarks about hydroxychloroquine “dangerous.”

He added: “I don’t know whether he is taking it or not. I know him saying he is taking it, whether he is or not, is reckless, reckless, reckless.”

The revelation was also noted in China.

Hu Xijin, editor of the Global Times, said Trump was leading the US response to the pandemic with “witchcraft”.

Dr Sean Conley, physician to the president, said in a statement issued through the White House later on Monday that Trump was in "very good health" and "symptom-free".

The US Navy officer added: "After numerous discussions he and I had regarding the evidence for and against the use of hydroxychloroquine, we concluded the potential benefit from treatment outweighed the relative risks."