DEA chief Chuck Rosenberg called medical marijuana “a joke” last week, and now patients and legalization advocates are hoping to have the last laugh. More than 18,000 people have signed a petition calling for Rosenberg's resignation.

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The petition was created by Marijuana Majority, a legalization advocacy organization, and in less than five days, thousands of medical marijuana patients have weighed in on Rosenberg’s comments, which ATTN: recently debunked.

Here's what Rosenberg said at a Q&A with reporters last week:

"What really bothers me is the notion that marijuana is also medicinal—because it's not. We can have an intellectually honest debate about whether we should legalize something that is bad and dangerous, but don't call it medicine—that is a joke."

But those remarks fly in the face of scientific evidence.

The DEA is responsible for enforcing the Controlled Substances Act, a list of what they deem the most dangerous drugs currently outlawed in the U.S. Under that act, marijuana is a Schedule 1 drug, which means the DEA considers it as dangerous and addictive as heroin.

It also means that American universities and research institutions are effectively barred from obtaining federal grants for marijuana research. If U.S. researchers could investigate the medical benefits of marijuana, they'd likely find what a number of international institutions have already determined: marijuana is effective at treating a range of health disorders, including chronic pain, insomnia, epilepsy, and anxiety.

In a statement to the Washington Post, the DEA clarified Rosenberg's statement. The spokesperson said:

"To clarify, Acting Administrator Rosenberg indicated that marijuana should be subject to the same levels of approval and scrutiny as any other substance intended for use as a medicine. DEA supports efforts to research potential medical uses of marijuana. To this end, DEA has never denied a registration request from anyone conducting marijuana research using FDA approved protocols."