Kratom

Traditional use in Southeast Asia

Kratom is the leaf of Mitragyna speciosa, a tropical evergreen tree in the coffee family that is native to Southeast Asia. The National Center for Complementary and Integrative Health (NCCIH) states that in Southeast Asia people have traditionally chewed the leaves or brewed them as tea to fight fatigue and improve work productivity, and that the leaves have also been used in religious ceremonies, for pain and diarrhea, and sometimes in place of opium.

A comprehensive review reports that the leaves have been used for centuries in Thailand, Malaysia and Myanmar, and that rural workers used them to relieve pain, lift mood and counter fatigue. A 2024 ethnobotanical review lists a much wider set of folk uses, including fever, cough, anxiety, diarrhea, wound healing and diabetes, and states that its aim is to examine the scientific studies behind these folkloric claims. The reviews cited here are secondary sources, and they do not give dated primary records for individual uses.

Spread to the United States and Europe

The National Institute on Drug Abuse (NIDA) states that use in the United States appears to have grown over roughly two decades, although estimates vary, and reports that about 0.6 percent of people aged 12 or older reported past-year use in 2021. The Food and Drug Administration (FDA) cites a national survey estimating about 1.7 million Americans aged 12 and older used kratom in 2021. A review of the literature adds that use is also described as rising in Europe and Japan.

In Western countries, the sources describe people using kratom to manage pain or opioid withdrawal symptoms, and the FDA lists self-treatment of pain, cough, diarrhea, anxiety, depression, opioid use disorder and opioid withdrawal. A poison center study describes the plant as having gained national attention in the United States for use in the self-management of opioid withdrawal and pain, alongside concerns about its safety.

Names and the plant

The sources use kratom both for the tree, Mitragyna speciosa, and for products made from its leaves. NIDA describes the term as commonly referring to an herbal substance that can produce opioid-like and stimulant-like effects. NCCIH describes the tree as native to Thailand and neighboring countries, and the 2024 ethnobotanical review uses the botanical name Mitragyna speciosa together with the family name Rubiaceae.

The main alkaloids

Kratom leaves contain many alkaloids; the FDA reports more than 50, and a review reports more than 40. Most research concerns mitragynine and 7-hydroxymitragynine, often abbreviated 7-OH. NIDA states that mitragynine breaks down in the body into 7-hydroxymitragynine. The FDA notes that 7-hydroxymitragynine makes up less than 2 percent of the total alkaloid content of leaves.

Relationship to other Machipedia pages

Kratom is one of the botanical products covered under the Herbal Medicine family on Machipedia, and that page should be consulted for the general framing of plant remedies. Related pages include Plant Medicine, Kava, CBD Supplements and Dietary Supplements. Kratom is a different plant from kava, and the sources reviewed here do not compare the two. In the United States, kratom products are sold as herbal supplements, according to NIDA.

Forms of kratom products

NIDA describes kratom as taken in capsules, powder, tea or liquid extract. A comprehensive review describes traditional preparation as a decoction or tea made from the leaves, or leaves ground into a powder, and describes modern products as powders, capsules and extracts that are largely unregulated. The same review reports that mitragynine content varies considerably between products. This page does not describe amounts, preparation or sourcing.

Pharmacology as sources describe it

The FDA states that mitragynine and 7-hydroxymitragynine act on the same brain mu-opioid receptors as opioids such as codeine, and that mitragynine also acts on serotonin, dopamine, norepinephrine and kappa opioid receptors. NIDA states that both compounds partially activate mu-opioid receptors and that their effects only partially resemble those of opioids such as heroin or oxycodone. A comprehensive review notes that sources disagree on whether the compounds are full agonists or partial agonists and mixed agonist-antagonists at opioid receptors.

On potency, the FDA states that 7-hydroxymitragynine has considerably higher mu-opioid receptor potency than mitragynine and than morphine. The comprehensive review gives figures of roughly 46 times mitragynine and 13 times morphine, and says the claim that 7-hydroxymitragynine is the main active compound has been shown only in animal models. A 2026 systematic review of preclinical studies reports effects at mu-opioid, adrenergic and serotonergic receptors and notes limits in pharmacokinetic data and standardized dosing.

Uses people report

Traditional claimed uses reported in the sources are relief of fatigue, support for work, pain and diarrhea. In the United States and Europe, people report using kratom for chronic pain, opioid withdrawal and opioid use disorder, and for anxiety, depression, cough and diarrhea, as the FDA lists. NIDA states that effects vary with dose, product, other substances and the individual, and describes users reporting stimulant-like effects at lower doses and opioid-like and sedative-like effects, with the caveat that these patterns are not firmly established.

Use as a substitute for other drugs

A comprehensive review states that kratom may serve some people as a substitute for more harmful drugs, but that there is little evidence supporting its use in place of established opioid replacement therapies. The authors describe its efficacy for opioid dependence or withdrawal as highly questionable and state that there is no reliable clinical evidence that it works as an opioid replacement.

Human trials and systematic reviews

A 2021 systematic review searched PubMed and Medline and identified 57 preclinical and 18 clinical studies on therapeutic potential and safety. Its pain and opioid withdrawal findings rest mainly on animal studies, in rodents, dogs and zebrafish. The abstract counts two interventional human studies. One was a 1932 study of five volunteers; the other was a randomized, placebo-controlled, double-blind study of 26 regular male users, in which pain tolerance to a cold stimulus increased one hour after a kratom decoction. The authors call the evidence encouraging and state that validation in large controlled clinical trials is required.

NCCIH states that very little human research has evaluated kratom, that its safety and possible therapeutic uses remain largely unknown, and that kratom has not been shown to be effective for withdrawal or any other medical use. The sources reviewed do not report a controlled trial establishing efficacy for chronic pain or for opioid withdrawal in people. Searches of PubMed for kratom systematic reviews and clinical evidence returned only the preclinical-dominated reviews cited here.

Public-health summaries

NIDA states that kratom has not been shown to be effective or safe for any medical purpose, that there are no uses approved by the FDA, and that NIDA and partners are studying it as a potential treatment for chronic pain, opioid withdrawal and opioid use disorder, including development of kratom-derived medications. The FDA states that it continues to warn consumers not to use kratom because of the risk of serious adverse events, that no FDA-approved kratom drug products exist, and that few well-designed human studies exist.

A review from 2020 describes no published guidelines specifically addressing kratom and states that management of adverse effects is extrapolated from opioid care. The sources reviewed here include no consensus statement from the National Academies; this page does not report one.

Documented harms

The FDA identifies liver toxicity, seizures and substance use disorder as serious risks, and states that opioid-type effects include sedation, nausea or vomiting, constipation, physical dependence and withdrawal, and respiratory depression that may be fatal. NIDA states that neither kratom leaves nor mitragynine appear in general to cause the breathing suppression typical of a fatal opioid overdose, while 7-hydroxymitragynine produced respiratory depression in laboratory models, and that long-term effects are poorly understood.

NCCIH lists mild effects such as nausea, constipation, dizziness and drowsiness, and rare serious effects including seizures, high blood pressure and liver problems. A comprehensive review describes liver injury as often cholestatic.

Poison center and mortality data

A study of National Poison Data System records identified 1,807 kratom exposures reported to United States poison centers in 2011 through 2017. Among first-ranked exposures, 31.8 percent resulted in admission to a health care facility and 51.9 percent in a serious medical outcome. There were 11 deaths associated with kratom exposure, two after exposure to kratom only, and multiple-substance exposures carried higher odds of serious outcomes. The abstract reports seven neonatal exposures, five with withdrawal.

A CDC report on 27 states found that 152 of 27,338 overdose deaths in July 2016 through December 2017 tested positive for kratom, with kratom listed as a cause of death in 91. Fentanyl was detected in 65.1 percent of kratom-positive deaths. The authors state that the extent to which kratom contributes to fatal overdoses cannot be determined.

Dependence, withdrawal and pregnancy

NIDA states that mild to moderate withdrawal symptoms can occur when regular use stops and that no medical treatments are approved for kratom withdrawal or use disorder. The FDA describes use disorder cases involving cravings, tolerance and withdrawal. A 2021 review of observational studies found moderate-to-severe dependence in some regular users.

On pregnancy, NIDA states that research is very limited and that case reports describe opioid-like neonatal abstinence syndrome in infants whose mothers regularly used kratom, often with other substances also involved. The FDA states that it is aware of newborns exposed before birth who showed jitteriness, irritability and muscle stiffness.

Contaminated products and why natural does not mean safe

CDC's final update on a 2018 outbreak reported 199 people infected with Salmonella in 41 states, 50 hospitalized and no deaths, with kratom the likely source and no single supplier identified. NIDA and the FDA also report heavy metal contamination. The sources describe kratom as a plant product that acts on opioid receptors and carries the risks described here, so plant origin is not itself a safety assurance.

Where to seek help

NIDA lists, for people in the United States, 911 for emergencies, poison control at 1-800-222-1222, the 988 crisis line, and the SAMHSA National Helpline at 1-800-662-4357. It also states that its information does not replace care.