More than 100,000 people have called on President Barack Obama to fire the new Drug Enforcement Administration chief after he called medical marijuana "a joke."

When the new DEA chief took office, marijuana policy reformers hoped for someone a bit friendlier to their cause. But Chuck Rosenberg seems to be dashing those hopes: First, he struggled to admit that marijuana is a safer drug than heroin. And now, in his latest controversial comments, he said it's "a joke" to consider marijuana medicine.

"What really bothers me is the notion that marijuana is also medicinal — because it's not," Rosenberg told reporters, according to CBS News. "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."

We’re delivering these medical #marijuana petitions to DEA tomorrow. Not too late to join: https://t.co/JIv1QswYSY pic.twitter.com/W5Mjb5XeKu — Marijuana Majority (@JoinTheMajority) November 19, 2015

What might seem like a joke to Rosenberg is actually a lifesaver to a lot of Americans. And a lot of these patients are voicing their anger: As of Friday, more than 100,000 people signed a Change.org petition calling on President Barack Obama to fire the DEA chief for his comments.

"My mom uses medical marijuana to deal with the severe pain caused by multiple sclerosis," Tom Angell, founder and chairman of Marijuana Majority, the organization that started the petition, said in a statement. "This issue is not a laughing matter for her and millions of other people who have seen the benefits of cannabis for themselves."

The upset petitioners have a lot of science behind them: There is an ample, growing body of evidence that marijuana does indeed possess medicinal value, and there's even evidence that the plant itself — because of its combination of chemicals — can be a particularly potent medication.

The research shows marijuana has medical value

In his comments, Rosenberg suggested that there's no evidence marijuana can act as medicine. "There are pieces of marijuana — extracts or constituents or component parts — that have great promise" medicinally, he said. "But if you talk about smoking the leaf of marijuana — which is what people are talking about when they talk about medicinal marijuana — it has never been shown to be safe or effective as a medicine."

First, plenty of people include non-smoked forms of pot in their definition of medical marijuana. The pro-legalization Marijuana Policy Project considers New York to have legalized medical marijuana even though the state doesn't allow its smoked form.

But more importantly, there's very solid research showing that marijuana — even in its smoked form — possesses medicinal value. The best study done to date, published in the Journal of the American Medical Association, reviewed the research and concluded that pot — again, including its smoked form — can effectively treat chronic pain and muscle spasticity. The study didn't rule out other potential medicinal benefits, but those were the two it found the best evidence for.

The chronic pain finding suggests marijuana can literally save lives

Other evidence has also found that some of pot's benefits are strengthened when the entire plant is used. This is because of what's known as the "entourage effect": Various compounds work together in marijuana to create a stronger effect. Since it's unclear which of pot's more than 500 active ingredients and 70 cannabinoids best compound one another, scientists aren't yet able to pick specific ingredients they want from marijuana to make a very focused drug. This means that under the current science, the best option for some patients is to use the full marijuana plant, smoked or not, as their medicine.

And while there's been a lot of worrying about whether smoking marijuana can have dangerous downsides, research on whether smoked marijuana causes lung disease or cancer has yielded conflicting results, with studies that control for tobacco smoking finding no significant effect from marijuana on lung cancer risk.

The chronic pain finding is perhaps the most promising in all the research: It suggests marijuana can literally save lives. As the country struggles with an opioid painkiller and heroin epidemic that is killing tens of thousands of people each year, the potential of a relatively safe drug like marijuana to substitute for dangerous opioids is a promising possibility.

Medical marijuana legalization literally saves lives

Since the late 1990s, the number of people dying from opioid painkiller overdoses has steadily risen — with more than 16,000 deaths reported in 2013. What's worse, one study in JAMA Psychiatry found opioid painkiller use has contributed to the rising use of heroin, which is deadlier and more addictive than painkillers. And a 2015 CDC analysis found people who are addicted to prescription painkillers are 40 times more likely to be addicted to heroin.

But these concerning numbers come into conflict with another medical issue: About 100 million Americans suffer from chronic pain, according to a 2011 report from the Institute of Medicine. And although there's no good evidence to suggest that opioid painkillers are a good treatment for chronic pain, they can help with acute pain and are commonly prescribed for long-term issues.

"Providing broader access to medical marijuana may have the potential benefit of reducing abuse of highly addictive painkillers"

If marijuana can relieve pain, it can substitute opioid painkillers with none of these problems. No one has ever reportedly died from a marijuana overdose. And pot isn't an opioid, so dependence — which does happen with marijuana, but at much lower rates than opioid addiction — can't lead to an addiction to heroin.

The potential benefits of the substitution effect aren't just theoretical. In a paper that looked at the effect of medical marijuana laws, RAND Corporation and University of California Irvine researchers concluded, "Our findings suggest that providing broader access to medical marijuana may have the potential benefit of reducing abuse of highly addictive painkillers." Another study published in JAMA found that medical marijuana laws may reduce opioid overdose deaths.

So what may seem like a joke to the current DEA chief actually has plenty of evidence to support it. Of course, it's the DEA's official stance that pot has no medical value, so Rosenberg's comment isn't too surprising. But positions like his increasingly fly in the face of the science — and may actually put people's lives at risk when adopted as the government's policy.