UPDATE (January 2017): The Drug Enforcement Administration (DEA) sought public comment on its decision to add kratom to Schedule I. The comment period has closed. The Drugs & Health Blog will provide an update when more information is available.

UPDATE (September 2016): On August 31, 2016, the Drug Enforcement Administration (DEA) published in a notice of intent to temporarily place two opioid-like chemicals found in the kratom plant, mitragynine and 7-hydroxymitragynine, in Schedule I.

Substances with a Schedule I classification, according to the DEA, could easily be abused and don’t currently have an accepted medical use in the U.S. (Other Schedule I substances include heroin, marijuana, and LSD.)

The DEA received numerous comments from researchers, members of the public, and congress expressing concerns about this action. In response the DEA has withdrawn its notice of intent and is soliciting public comments on this issue. Instructions for providing comments can be found here.

Kratom is a tropical tree found in Southeast Asia, with leaves that contain some of the same chemicals found in opioids. Some people—especially in areas of the world where kratom trees are common—use it as a stimulant.

Kratom isn’t currently an illegal substance, and has been easy to order on the Internet in recent years. In spite of its easy availability, however, we’re still learning about kratom’s effects on a person’s brain and body. Here are some things we know about kratom—and just as important, what isn’t known yet.

What’s known about it

People have used kratom leaves as a stimulant, for pain relief, or to improve mood. The leaves have a bitter taste, and are sometimes made into powder for tea, chewed or smoked, or eaten in food.

Kratom may also be sold as a leaf, powder (sometimes in packets labeled “not for human consumption”), or extract, with names like Herbal Speedball, Biak-biak, Ketum, Kahuam, Itrhang, or Thom.

If you consume kratom, you could have some uncomfortable and possibly dangerous side effects: nausea, itching, sweating, increased sensitivity to sunburn, loss of appetite, and, for some users, psychotic symptoms (bizarre behavior, strange beliefs, hearing voices, etc.).

Kratom users might also experience long-lasting health effects: difficulty sleeping (insomnia), frequent urination, darkening of the skin, dry mouth, and anorexia (an intense fear of gaining weight, which can lead a person to dramatically reduce the amount of food they eat and resist maintaining a healthy weight).

Commercial forms of kratom are sometimes laced with other compounds that have caused deaths.

What we don’t know

It isn’t clear yet whether kratom is addictive, but users can become dependent on it: Their bodies will have side effects if they try to stop using it. Some users have reported becoming addicted to kratom, which means they go to great lengths to keep using it, even when there are negative consequences for their relationships, jobs, or health. Plus, a study in Thailand has found that people who use kratom over a period of several years have a much higher risk of using other substances—especially heroin, MDMA, and meth.

If kratom is addictive, we don’t know yet which kinds of treatment could help with the addiction.

It’s impossible to know what other ingredients may be mixed in with kratom that’s sold commercially. For this reason, the Food and Drug Administration (FDA) has warned people not to use any products labeled as containing kratom.

Consider the potential risks before you decide to use any drug. As with synthetic marijuana and other unregulated drugs, what we don’t know about kratom could end up being the most important information of all.

Learn the real facts about prescription stimulants.