Fox News reporter Geraldo Rivera on Friday joked that Democratic presidential candidate Bernie SandersBernard (Bernie) SandersHarvard law professor: Impeachment could worsen political dysfunction, polarization Gun control debate shifts to hardening schools after Texas shooting Bernie Sanders: NRA to blame for lack of action on gun control MORE's supporters must be on drugs to like him.

“Bernie Sanders is so clearly a fringe candidate,” Rivera said on "Fox & Friends." "It is charming to me that young people [support him]."

“Why is he leading by 20 [points] then?” retorted host Steve Doocy, pointing out that he nearly beat rival Hillary Clinton in the Iowa caucuses.

“Everyone’s smoking dope,” Rivera quipped.

Doocy took issue with Rivera’s assessment, asking, “What about Iowa? They’re not smoking dope in Iowa.”

“Iowa has got the famous writers’ workshop, Iowa State, Iowa University,” Rivera responded. "There are so many young folks there.”

Rivera compared Sanders to GOP presidential candidate Ted Cruz.

“Bernie Sanders, I think, is like Ted Cruz, as they’re both extremist candidates who will not be in the final mix,” he said.

Rivera tweaked rival network MSNBC for its handling of Thursday night’s Democratic debate.

“Wasn’t it revealing, though?” Rivera asked. "When Rachel Maddow comes up and hugs Hillary Clinton, it’s like saying, ‘Never mind, I didn’t mean any of that mean stuff.’ ”

Sanders has a big lead on Clinton in polls of New Hampshire. The state's primary is Tuesday.

Clinton won Monday's Iowa caucuses by just 0.2 percentage points.