“Late Show” host Stephen Colbert said President Donald Trump this week held an “insane” press conference in which he linked autism to a drug he couldn’t even pronounce.

“Autism is a simple term that actually covers a variety of developmental differences across the spectrum and you can’t blame anyone, even Donald Trump, for seeking answers,” Colbert said on Tuesday.

Then his tone shifted ― fast.

“But experts in the field caution that what President Trump said in his speech yesterday was ― and I don’t want to get bogged down in technical jargon here ― ‘fucking crazy,’” Colbert said.

Trump said the pain reliever acetaminophen (and brand name Tylenol) can cause autism and warned women not to take it during pregnancy. Experts, as Colbert noted, slammed the claim as “irresponsible” and “highly unsettling.”