There is no evidence that sunlight can cure coronavirus on the human body. Same for disinfectant and bleach. So, do not drink bleach. Do not inject disinfectant. And do not believe there is some cure for coronavirus coming from ultraviolet light.

During Thursday’s White House coronavirus briefing, a science administrator, Wiliam N. Bryan, said the government had tested how sunlight and disinfectants like bleach and alcohol can quickly kill Covid-19 on surfaces.

Hearing that, President Trump returned to the lectern. He speculated about injecting a disinfectant into a human body. He also wondered aloud whether hitting someone with a “tremendous” beam of light would kill the virus.

On Friday, Mr. Trump said he did not mean the suggestions. “I was asking a question sarcastically to reporters like you just to see what would happen,” he said.