At a press conference on Thursday night, US President Donald Trump pondered aloud whether shining "very powerful light" inside the human body or injecting "disinfectant" could kill off the coronavirus.

Doctors and the makers of disinfectants soundly decried the remarks and told people not to ingest such products, like bleach, because it is dangerous.

Trump said Friday that he was just being "sarcastic" when he mused about ingesting people with "light" and "disinfectant" to treat COVID-19.

The US Centers for Disease Control also reminded people that it's dangerous to ingest disinfectants, that they aren't effective against the coronavirus, and to only use them as the manufacturers intend.

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At a press conference on Thursday night, President Donald Trump pondered aloud whether shining "very powerful light" inside the human body or injecting "disinfectant" could kill off the coronavirus.

Experts immediately shot down the remarks as dangerous, and rushed to tell people not to do it.

Here's a breakdown of the entire saga:

Wednesday, April 22: A preliminary study is presented to the White House task force on the coronavirus

According to a Friday report from the Washington Post, the Department of Homeland Security's acting undersecretary for science and technology, William Bryan, presented a preliminary study (which has not been published in a peer-reviewed journal) about the "possibility of heat, humidity, and light to kill the virus, as well as the effectiveness of disinfectants in killing it on surfaces" to the coronavirus task force.

A source told The Post that some on the task force, including White House coronavirus response coordinator Dr. Deborah Birx and National Institute of Allergy and Infectious Diseases Director Anthony Fauci, expressed their concerns about the report and/or its presentation. But Vice President Mike Pence and others wanted Bryan to present the information at the briefing to give the public some good news, The Post reported.

Thursday, April 23: Before the White House press briefing

Dr. Deborah Birx, White House coronavirus response coordinator, listens as President Donald Trump speaks about the coronavirus in the James Brady Press Briefing Room of the White House, Thursday, April 23, 2020, in Washington. AP Photo/Alex Brandon

Coincidentally, about a half hour before the White House press briefing, the US Environmental Protection Agency posted a notice reminding Americans to handle disinfectants as the manufacturers intend. "Do not ingest disinfectant products," the agency warned.

Before the briefing began, Bryan gave Trump a "15-minute" presentation on the preliminary DHS study, the Post reported.

Bryan, The Post reported, was to present the study at the briefing, and Trump was to read prepared remarks.

Thursday, April 23: Trump makes the comments during the daily White House press briefing

Bryan presented the study, which focused on surfaces, not humans.

Trump, during his remarks, said the following, as transcribed by Business Insider's Grace Panetta:

"So I asked Bill a question some of you are thinking of if you're into that world, which I find to be pretty interesting. So, supposing we hit the body with a tremendous, whether its ultraviolet or just very powerful light, and I think you said, that hasn't been checked but you're gonna test it. And then I said, supposing it brought the light inside the body, which you can either do either through the skin or some other way, and I think you said you're gonna test that too, sounds interesting. And I then I see the disinfectant, where it knocks it out in one minute, and is there a way you can do something like that by injection inside, or almost a cleaning. Because you see it gets in the lungs, and it does a tremendous number on the lungs. So it'd be interesting to check that. So you're going to have to use medical doctors, but it sounds interesting to me, so we'll see. But the whole concept of the light, the way it goes in one minute, that's pretty powerful."

During the presentation, Birx was caught on camera reacting to Trump's comments, and when asked by Trump about using heat and light to treat viruses she said: "Not as a treatment. I mean, certainly, fever is a good thing. When you have a fever, it helps your body respond. But I've not seen heat or light."

Thursday, April 23: After the briefing, the fallout begins

Dr. Birx was captured on camera reacting to Trump's comments during the briefing. Phil Williams/Twitter; Business Insider

Some in the administration discouraged the thought. "No, I certainly wouldn't recommend the internal ingestion of a disinfectant," FDA Commissioner Stephen Hahn told CNN on Thursday night.

Doctors also began begging people not to ingest or inject disinfectants.

Friday, April 24: Companies and government agencies warn not to ingest or inject disinfectants

The US Centers for Disease Control, meanwhile, wasn't taking any chances. "Household cleaners and disinfectants can cause health problems when not used properly," it tweeted early on Friday.

The makers of Lysol, too, said in a statement on Friday that "under no circumstance should our disinfectant products be administered into the human body (through injection, ingestion or any other route)."

Burger King also tweeted, "not sure why we need to be the ones to tell you this, but don't drink bleach."

Disinfectant manufacturers reminded consumers not to ingest their products. Shoshy Ciment/Business Insider

Friday, April 24: The White House works to spin Trump's comments

By Friday morning, the White House press secretary Kayleigh McEnany was claiming the comments were merely taken "out of context."

Birx, asked about the president's comments, told Fox News for a segment that aired in full on Saturday, "When he gets new information he likes to talk that through, out loud, and really have that dialogue. And so that's what dialogue he was having."

By Friday afternoon, amid concern from medical professionals and ridicule from his critics, the president himself decided on a different approach: It had all been a joke, albeit an attempt at humor that no one seemed to get, Fox News included.

"I was asking a very sarcastic question to reporters in the room about disinfectants on the inside," Trump claimed.

Kayleigh McEnany, then the national press secretary for the Donald Trump 2020 presidential campaign, speaks at a "Keep America Great" campaign rally on January 9, 2020. Scott W. Grau/Icon Sportswire via Getty Images

Friday, April 24 through Sunday, April 26: Calls to poison control lines spike

As Business Insider's Panetta previously reported, "Maryland said its coronavirus hotline has received over 100 calls from people inquiring about President Trump's recent musings about ingesting disinfectant as a treatment for COVID-19."

Newsweek followed up that poison control center calls spiked in Illinois, Maryland, Michigan, and New York.

At Friday evening's press briefing, neither Trump nor Pence took questions from the press.