Doctors and health experts urged people not to drink or inject disinfectant on Friday after US President Donald Trump suggested scientists should investigate inserting the cleaning agent into the body as a way to cure Covid-19.

“This is one of the most dangerous and idiotic suggestions made so far in how one might actually treat Covid-19,” said Paul Hunter, a professor of medicine at Britain’s University of East Anglia. He said infecting disinfectants would be likely to kill anyone who tried it.

“It is hugely irresponsible because, sadly, there are people around the world who might believe this sort of nonsense and try it out for themselves,” he said.

Trump said at his daily media briefing on Thursday that scientists should explore whether inserting light or disinfectant into the bodies of people infected with the new coronavirus might help them clear the disease.

“Is there a way we can do something like that by injection, inside, or almost a cleaning?,” he said. “It would be interesting to check that.”

While ultraviolet (UV) light is known to kill viruses contained in droplets in the air, doctors say there is no way it could be introduced into the human body to target cells infected with Covid-19.

“Neither sitting in the sun, nor heating will kill a virus replicating in an individual patient’s internal organs,” said Penny Ward, a professor in pharmaceutical medicine at Kings College London.

“Drinking bleach kills. Injecting bleach kills faster. Don’t do either!,” she added.

Reckitt Benckiser, which manufacturers household disinfectants Dettol and Lysol, issued a statement also warning people not to ingest or inject its products. Parastou Donyai, director of pharmacy practice and a professor of social and cognitive pharmacy at the University of Reading, said Trump’s comments were shocking and unscientific.