Earlier this month, the Food and Drug Administration and the Centers for Disease Control and Prevention announced that they were investigating a multistate outbreak of salmonella infections. The agencies reported that 40 people in 27 states got sick, and 14 had been hospitalized. Investigators said that 17 of the 24 people they’ve interviewed reported consuming kratom before getting sick, and a strain of salmonella was identified in leftover kratom powder from people who got sick in North Dakota and Utah.

The news is the latest in a recent series of government announcements about kratom, an herb derived from the leaves of a Southeast Asian tree that many people say has helped them with pain, anxiety, and even symptoms of opioid withdrawal. Research has shown kratom’s potential as an opioid substitute, offering pain relief seemingly without the life-threatening side effect of respiratory depression. More research needs to be done, experts say, but they see important—even life-saving—potential.

The FDA hasn’t seen it that way. It’s continued to warn about the herb’s “potential for abuse, addiction, and serious health consequences” and the “deadly risks associated with kratom,” offering a dubious list of 36 (now 44) deaths associated with its use.

Last month, the FDA published the results of a computer model and misleadingly declared kratom an opioid, painting it as a problem rather than a possible treatment or alternative painkiller. It followed up less than two weeks later by persuading a Missouri-based manufacturer to recall and destroy a cache of more than 142,000 kratom-containing capsules, along with just over 11 kilograms of kratom powder, and stop selling any kratom-containing products. And it reiterated its stance against the herb, quoting FDA Commissioner Scott Gottlieb as saying:

“The extensive scientific data we’ve evaluated about kratom provides conclusive evidence that compounds contained in kratom are opioids and are expected to have similar addictive effects as well as risks of abuse, overdose and, in some cases, death. At the same time, there’s no evidence to indicate that kratom is safe or effective for any medical use.”

Scientists who’ve studied kratom disagree, and are concerned that government agencies—including the FDA and the Drug Enforcement Administration—are taking an unnecessarily hard line against the plant. In 2016, the DEA proposed using its emergency powers to declare kratom a Schedule I drug: illegal, unsafe, with a high potential for abuse, and no accepted medical use in the United States. (Heroin, ecstasy, and, yes, marijuana, are on that list.) But following public pressure—including a petition signed by 120,000 people—the agency backed off. Instead, the DEA asked the FDA to conduct a formal scientific evaluation of kratom and hold a public comment period to inform any decisions in the future.

Now, though, scientists and kratom advocates worry that the flurry of announcements mark a renewed push to criminalize the plant. Soon after the FDA labeled kratom an opioid, a group of researchers sent an open letter to Robert Patterson, the acting administrator of the DEA, and Kellyanne Conway, the Trump advisor leading the response to the opioid crisis, warning them that banning kratom could worsen the crisis. Specifically, they cautioned that classifying kratom as Schedule I could lead to more deaths, not fewer, as people who’d turned to kratom for pain relief or withdrawal treatment might return to opioids.

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The FDA claims that it’s following the evidence and acting in Americans’ best interests. “Our concerns related to this product, and the actions we’ve taken, are rooted in sound science and are in the interest of protecting public health,” it said on February 6. But in their letter, the scientists say the government is ignoring decades of research about kratom.

“We believe strongly that the current body of credible research on the actual effects of kratom demonstrates that it is not dangerously addictive,” they write, adding that the comparison to opioids is misleading. Kratom may act on opioid receptors in the brain but it “is distinct from classical opioids (e.g. morphine, heroin, oxycodone, etc.) in its chemistry, biological effects, and origin (kratom is a tree in the coffee family, not the opium poppy family).” As Columbia University pharmacologist Andrew Kruegel told Tonic last month, “The problem with saying it’s ‘an opioid’ without qualification is that it just paints everything with this broad brush, and obviously carries a negative connotation given what’s going on in the country right now.”

Furthermore, they say, criminalizing kratom would make it difficult to conduct more research—similar to the way federal laws have stymied the study of psychedelics and medical marijuana. Opioids—including prescription opioids, heroin, and fentanyl—killed a record 42,000 people in 2016, according to the CDC. In the face of all that death, the scientists write, “the federal government should be encouraging additional research into the potential benefits of kratom,” bringing scientific understanding to “breakthroughs in pain-relieving medicines that are so desperately needed.”

“What we’re seeing is a drug hysteria,” Zach Walsh, a psychologist who studies substance use at the University of British Columbia and a signatory of the letter, tells Tonic. “The claims that [the FDA is] making are really overblown. It’s a concern because there are reports that some people are using kratom to reduce their opioid use and to get over an opioid dependency.” But the FDA’s positioning of kratom as a deadly opioid makes following up on those reports that much more difficult.

“While we remain open to the potential medicinal uses of kratom, those uses must be backed by sound-science and weighed appropriately against the potential for abuse,” an FDA spokesperson tells Tonic. “They must be put through a proper evaluative process that involves the DEA and the FDA. To those who believe in the proposed medicinal uses of kratom, are encouraged to conduct the research that will help us better understand kratom’s risk and benefit profile, so that well studied and potentially beneficial products can be considered.” Again, such research would be restricted if kratom is placed into Schedule 1.

When asked about existing research showing that kratom works differently in the brain than opioids such as heroin and oxycodone, the FDA spokesperson said the agency has taken such research into consideration, but reiterated, “What’s important to remember is that there are no scientific data from studies of kratom in humans.” That data, the agency believes, would best be obtained as part of a drug development program—which is an unlikely prospect for a plant. In the meantime, the agency says it’s not collecting data about how many people may be using kratom to treat opioid withdrawal. “Kratom should not be used to treat any medical conditions,” the spokesperson said, “nor should it be used as an alternative to prescription opioids.”

A DEA spokesperson said the evaluation for scheduling kratom is ongoing, with no available timeframe for a decision. “Nothing would preclude DEA from considering additional scientific evidence from the FDA or other sources as part of our deliberations,” the spokesperson tells Tonic.

To be clear, scientists aren’t advocating for letting the kratom market run wild. “The common-sense approach would be to see this as a promising plant that we can investigate further, and regulate it as a health supplement,” Walsh says. And there are some indications the FDA (whose purview it is to regulate dietary supplements) is cleaning up the market.

Divinity Products, the Missouri-based company the FDA convinced to destroy its supply, had long advertised its wares as being “FDA compliant,” saying there were “processed according to strict FDA quality guidelines”—and, since there aren’t any FDA guidelines for kratom quality, that was not true. It also touted the painkilling power of kratom; and by making a medical claim, Divinity opened itself up to FDA sanctions. Soon after shutting down Divinity’s kratom business, the agency warned another vendor about making unproven medical claims. The scuttlebutt among vendors is that the FDA is looking to sweep up any company running afoul of the law.

That’s the kind of regulation that scientists and kratom advocates would like to see: consumer protection and quality control. Jack Henningfield is an adjunct professor of behavioral biology at the Johns Hopkins University School of Medicine who also signed the letter to Patterson and Conway. He says he’s impressed by the FDA’s efforts to combat the opioid crisis, but “perplexed” by its position on kratom, which he calls “far behind the current state of the science.” Dubbing kratom an opioid is inappropriate, and “implying it is not helpful to people in efforts to manage opioid withdrawal and abstain from opioids ignores decades of published experience,” Henningfield says.

He frequently works with the FDA on issues related to drug scheduling and addiction as a consultant for Pinney Associates, and he’d like to see the agency use its authority to improve public health. “There’s a lot that the FDA can do that would help clean up the marketplace,” Henningfield tells Tonic. Henningfield’s firm began consulting with the American Kratom Association (AKA), an advocacy group, in 2016, when the DEA sought to ban the herb. “We did that because we felt DEA was wrong on the science and would create a public health problem,” he says.

Since then, he’s worked with the AKA to develop a set of principles the FDA could use to regulate kratom. They include holding accountable manufacturers who make scientifically unsupported claims—just as the agency has done with at least two companies. But instead of an outright ban, the regulations would seek to ensure the safety and purity of kratom products, keep them out of the hands of children, and make sure they’re properly labeled.

Henningfield and the nine scientists who signed the letter believe that’s a common-sense approach to kratom: regulate it, make it safe, and restrict it to adults. “That’s what I’d love to see FDA do,” he said, “That’s what would serve public health.”