The U.S. Drug Enforcement Administration appeared to concede Wednesday that it had been too hasty in attempting to ram through a controversial ban on the herbal supplement kratom.

In a notice set to be published in the Federal Register, the DEA said it has formally withdrawn an August announcement that initially outlined plans to place mitragynine and 7-hydroxymitragynine, two active compounds in kratom, in Schedule I. Schedule I drugs include heroin and LSD and are considered to have no known medical benefit and a high potential for abuse.

Citing widespread backlash from kratom users, advocates and other stakeholders, the DEA says it will open an official comment period, set to end on Dec. 1. It is also asking the U.S. Food and Drug Administration for a formal scientific and medical evaluation of the herb, which will be used to make an updated scheduling recommendation.

Kratom is an herb made from the leaves of Mitragyna speciosa, a Southeast Asian tree related to coffee. The alkaloids mitragynine and 7-hydroxymitragynine appear to activate opioid receptors in the brain and reduce pain. And although most opioids have sedative qualities, low to moderate doses of kratom actually serve as a mild stimulant.

All of this has made kratom a popular traditional medicine for millennia in Asia and more recently in the West, where many users tout it not just as an analgesic, but also as a treatment for anxiety, depression and opioid addiction.

But the DEA has raised concerns about kratom’s addictive potential, as well as isolated reports of harm associated with use. The agency’s change in course will keep kratom legal for the immediate future, but it’s unclear how long the delay will last.

The DEA will take submitted comments and the FDA’s findings into consideration as it decides how to proceed. If it determines after Dec. 1 that there is “substantial evidence of potential for abuse to support” scheduling kratom, the agency can take additional action through the permanent or temporary scheduling process. To ban kratom on a permanent basis, the DEA would need to submit an additional notice of proposed rulemaking, which would allow for further input from the public and lawmakers.

But if the DEA maintains, as it did in August, that emergency scheduling of kratom is “necessary to avoid an imminent hazard to the public safety,” it could file a new notice of intent, which would likely go into effect a month later. The agency could also opt to pursue both emergency and permanent scheduling simultaneously, or to leave kratom unregulated.

Still, the DEA’s decision to reverse course on banning a drug, even temporarily, is unprecedented. Kratom and drug policy reform advocates who have spent the past month aggressively lobbying against the ban effort were quick to hail the news as a victory.

“This is a truly remarkable moment to see the Drug Enforcement Administration, a law enforcement agency with a long track record of ignoring both science and public opinion, being forced to consider the scientific evidence and public opinion before taking additional steps with respect to kratom,” said Grant Smith, deputy director of national affairs at the Drug Policy Alliance, in a statement. “People who oppose a federal kratom ban only have about six weeks to tell the federal government that kratom does not belong in our broken drug scheduling system.”

Susan Ash, founder of the American Kratom Association, a nonprofit that works with consumers, credited the effort by kratom users, congressional lawmakers and scientists who have challenged the DEA’s unilateral move to expand the drug war.

“We believe kratom should not be scheduled in any way, shape or form,” she said in a statement to The Huffington Post. “It’s been consumed safely for decades in the U.S. and world-wide for millennium, so there is no impetus to make it a controlled substance. We look forward to working cooperatively with the DEA as they conduct their review.”

Earlier this month, two groups of senators wrote acting DEA administrator Chuck Rosenberg asking him to delay the kratom ban. Sen. Cory Booker (D-N.J.) said in a letter that a group of 11 scientists from “well-respected research institutions in the U.S.” had contacted him to express concern about the agency’s crackdown. They pointed out that a number of initial studies on kratom have shown the herb to have therapeutic potential, with relatively few risk factors. Some research has even suggested that kratom could aid in the development of safer, non-opioid painkillers, which are currently contributing to a national epidemic of addiction and overdose.

The Senate letter built on a similar push by a group of 50 House lawmakers, led by Rep. Mark Pocan (D-Wis.), as well as a White House petition that now has more than 140,000 signatures. In a statement to HuffPost on Wednesday, Pocan called the DEA’s move toward transparency a good step forward. The next step, he suggested, should be to make the ban’s delay permanent.

“I hope the DEA will take a hard look at the federally funded research into the potential health benefits of kratom, especially with regards to curbing opioid abuse and addiction,” said Pocan. “Concerned citizens across the country have made it clear, they want the DEA to listen to the science when it comes to the potentially life-saving properties of kratom. I hope a more thorough process will reverse their decision, and allow for continued research in this area