Doctors warned the president's idea could have fatal results.
Pulmonologist Dr Vin Gupta told NBC News: "This notion of injecting or ingesting any type of cleansing product into the body is irresponsible and it's dangerous.
"It's a common method that people utilise when they want to kill themselves."
Kashif Mahmood, a doctor in Charleston, West Virginia, tweeted: "As a physician, I can't recommend injecting disinfectant into the lungs or using UV radiation inside the body to treat Covid-19.
"Don't take medical advice from Trump."
John Balmes, a pulmonologist at Zuckerberg San Francisco General Hospital, warned that even breathing fumes from bleach could cause severe health problems.
He told Bloomberg News: "Inhaling chlorine bleach would be absolutely the worst thing for the lungs. The airway and lungs are not made to be exposed to even an aerosol of disinfectant.
"Not even a low dilution of bleach or isopropyl alcohol is safe. It's a totally ridiculous concept."
Mr Trump has previously hyped a malaria medication, hydroxycloroquine, as a possible treatment for coronavirus, though he has stopped touting that drug recently.
This week a study of coronavirus patients in a US government-run hospital for military veterans found more deaths among those treated with hydroxychloroquine than those treated with standard care.
Reacting to the president's remarks on Thursday evening, Joe Biden, his likely Democratic challenger in November's White House election, tweeted: "UV light? Injecting disinfectant? Here's an idea, Mr President: more tests. Now. And protective equipment for actual medical professionals."