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Kratom is an herbal made from leaves of a tropical evergreen tree (Mitragyna speciosa) that is native to Southeast Asia.  Extracts from the leaves of the kratom tree have psychotropic and opioid-like activity, which has led to their use as a recreational drug.  Kratom has been linked to rare instances of clinically apparent acute liver injury.



Kratom is a botanical extract derived from the leaves of a tropical evergreen tree (Mitragyna speciosa), which belongs to the coffee family and is indigenous to Thailand, Myanmar and Malaysia.  In Southeast Asia, kratom has been used for decades as an herbal medication to treat chronic pain, increase energy and stamina, treat chronic pain and diarrhea, and as a substitute for opium or for opium withdrawal.  The leaves have multiple components, including psychoactive alkaloids that have opioid-like activity.  In many Southeast Asian countries, chewing Mitragyna speciosa leaves is a not uncommon practice and not considered addictive.  The effects of chewing kratom leaves include enhanced alertness, talkativeness and sociability.  Extracts of kratom have been used to treat chronic pain, diarrhea and cough.  The psychoactive effects of kratom have led to its use recreationally as a cannabis-like drug.  Higher doses can cause agitation, hypertension, dyspnea and confusion.  Overdoses of kratom can cause seizures, coma and death.  Kratom has become a substance of abuse and it has not been shown to have any beneficial medical uses.  In 2014, the US FDA banned the inclusion of kratom in dietary supplements because of safety concerns, with potential adverse effects including respiratory depression, aggression, hallucinations, delusions, insomnia, vomiting and severe withdrawal.



Chronic use of kratom recreationally has been associated with rare instances of acute liver injury.  The onset of injury is usually within 2 to 8 weeks of starting regular use of kratom powder or tablets, with symptoms of fatigue, nausea, pruritus and dark urine followed by jaundice.  The pattern of liver injury is typically cholestatic and can be severe with serum bilirubin levels rising above 20 mg/dL.  The severe cholestasis can be accompanied by acute renal failure and bone marrow toxicity.  Fever is common, but not rash or eosinophilia and autoantibodies are usually absent.  The cholestasis can be prolonged, but usually resolves spontaneously.  Corticosteroids have been used in cases of suspected kratom hepatotoxicity, but their efficacy is unproven.


Drug Class:  Herbal and Dietary Supplements


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Clinical cases of drug-induced liver injury that have been submitted to LiverTox ("Submit a Case Report") are available for review.  Most of these reference cases are from the Drug-Induced Liver Injury Network, but others are from users of LiverTox who have submitted data from an actual clinical case.  All cases have been reviewed and cleared of personal identifiers and a brief comment added by the LiverTox editors.  Click on the following link to view the submitted case reports that have been made publically available.

Submitted Cases on Kratom


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Kratom – Generic


Herbal and Dietary Supplements



Fact Sheet at DEA, Office of Diversion Control, Drug & Chemical Evaluation Section


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Kratom S900005870 Herbal mixture Not applicable

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References updated:  23 May 2014

  1. Zimmerman HJ. Unconventional drugs. Miscellaneous drugs and diagnostic chemicals. In, Zimmerman, HJ. Hepatotoxicity: the adverse effects of drugs and other chemicals on the liver. 2nd ed. Philadelphia: Lippincott, 1999: pp. 731-4.  (Expert review of hepatotoxicity published in 1999; kratom is not discussed).

  2. Seeff L, Stickel F, Navarro VJ. Hepatotoxicity of herbals and dietary supplements. In, Kaplowitz N, DeLeve LD, eds. Drug-induced liver disease. 3rd ed. Amsterdam: Elsevier, 2013, pp. 631-58.  (Review of hepatotoxicity of herbal and dietary supplements [HDS]; kratom is not discussed).

  3. Drug Enforcement Administration. Kratom(Mitragyna speciosa korth).

  4. Chalasani N, Fontana RJ, Bonkovsky HL, Watkins PB, Davern T, Serrano J, Yang H, Rochon J; Drug Induced Liver Injury Network(DILIN). Causes, clinical features, and outcomes from a prospective study of drug-induced liver injury in the United States. Gastroenterology 2008; 135: 1924-34. PubMed Citation  (Among 300 cases of drug induced liver disease in the US collected between 2004 and 2008, 9% were attributed to herbals and dietary supplements, but none to kratom).

  5. Reuben A, Koch DG, Lee WM; Acute Liver Failure Study Group. Drug-induced acute liver failure: results of a U.S. multicenter, prospective study. Hepatology 2010; 52: 2065-76. PubMed Citation  (Among 1198 patients with acute liver failure enrolled in a US prospective study between 1998 and 2007, 133 were attributed to drug induced liver injury, including 12 [9%] attributed to herbals, but none to kratom).

  6. Nelsen JL, Lapoint J, Hodgman MJ, Aldous KM. Seizure and coma following Kratom(Mitragynina speciosa Korth) exposure. J Med Toxicol 2010; 6: 424-6. PubMed Citation  (64 year old man developed seizures and coma shortly after ingesting kratom tea and datura stramonium [Jimson weed with anticholinergic activity], having high levels of both in urine, awaking after 24 hours and admitting to chronic use of kratom for chronic pain).

  7. Ward J, Rosenbaum C, Hernon C, McCurdy CR, Boyer EW. Herbal medicines for the management of opioid addiction: safe and effective alternatives to conventional pharmacotherapy? CNS Drugs 2011; 25: 999-1007. PubMed Citation  (Review of herbal medications that are used for opioid addiction and withdrawal; there have been no formal trials of the efficacy and safety of kratom for withdrawal symptoms).

  8. Kapp FG, Maurer HH, Auwärter V, Winkelmann M, Hermanns-Clausen M. Intrahepatic cholestasis following abuse of powdered kratom(Mitragyna speciosa). J Med Toxicol 2011; 7: 227-31. PubMed Citation  (25 year old man developed fever and abdominal pain followed by jaundice a week after stopping a 2 week course of kratom powders [bilirubin 31.9 mg/dL, ALT 94 U/L, Alk P 173 U/L], liver biopsy showing bland cholestasis, with slow and spontaneous improvement).

  9. Schmidt MM, Sharma A, Schifano F, Feinmann C. "Legal highs" on the net-Evaluation of UK-based Websites, products and product information. Forensic Sci Int 2011; 206: 92-7. PubMed Citation  (Internet searches for "legal highs" identified several hundred websites offering various products [pills, smoking materials, powders, teas], 92% of which did not list ingredients and 92% failing to mention side effects, most common products being Salvia divinorum and kratom).

  10. Kronstrand R, Roman M, Thelander G, Eriksson A. Unintentional fatal intoxications with mitragynine and O-desmethyltramadol from the herbal blend Krypton. J Anal Toxicol 2011; 35: 242-7. PubMed Citation  (9 cases of fatal overdose of "Krypton" were identified over a 1 year period [2009-2010] in Sweden; 7 men and 2 women, ages 22 to 35 years, found dead or presenting in shock and asystole with lung and brain edema in all and liver steatosis in one; Krypton consists of powder extracts of kratom leaves and the mu-opioid agonist, O-desmethyltramadol, the major active metabolite of tramadol).

  11. Holler JM, Vorce SP, McDonough-Bender PC, Magluilo J Jr, Solomon CJ, Levine B. A drug toxicity death involving propylhexedrine and mitragynine. J Anal Toxicol 2011; 35: 54-9. PubMed Citation  (20 year old man was found death with no signs of trauma, but a history of kratom ingestion and autopsy showing pulmonary edema and presence of propylhexedrine, and kratom in urine).

  12. Rosenbaum CD, Carreiro SP, Babu KM. Here today, gone tomorrow... and back again? A review of herbal marijuana alternatives (K2, Spice), synthetic cathinones (bathsalts), kratom, Salvia divinorum, methoxetamine, and piperazines. J Med Toxicol 2012; 8: 15-32. PubMed Citation  (Review of herbal alternatives to marijuana for euphoric effects, including kratom which has stimulatory effects at low doses and opioid-like effects at higher doses, and is available through the internet as powders, leaves, teas or as tablets, sometimes combined with other opiate-like agents).

  13. Prozialeck WC, Jivan JK, Andurkar SV. Pharmacology of kratom: an emerging botanical agent with stimulant, analgesic and opioid-like effects. J Am Osteopath Assoc. 2012; 112: 792-9. PubMed Citation  (Concise review of chemical constituents, pharmacology, clinical effects, uses and safety of kratom).

  14. Forrester MB. Kratom exposures reported to Texas poison centers. J Addict Dis 2013; 32: 396-400. PubMed Citation  (Between 2009 and 2013, there were 14 reports of kratom exposures to the Texas Poison center, but none between 1998 and 2008; adverse events being tachycardia, agitation, nausea, vomiting, tremor, sweating, diaphoresis, drowsiness and hallucinations but no deaths).

  15. Neerman MF, Frost RE, Deking J. A drug fatality involving Kratom. J Forensic Sci 2013; 58 Suppl 1: S278-9. PubMed Citation  (17 year old man was found dead with empty bottles and boxes of kratom, autopsy showing bilateral pulmonary edema and high mitragynine blood levels).

  16. Ulbricht C, Costa D, Dao J, Isaac R, LeBlanc YC, Rhoades J, Windsor RC. An evidence-based systematic review of kratom (Mitragyna speciosa) by the Natural Standard Research Collaboration. J Diet Suppl 2013; 10:152-70. PubMed Citation  (Systematic review of safety and efficacy of kratom [Mitragyna speciosa] concludes that there is a lack of evidence in support of kratom having any clinical indication, its historic uses being as an analgesic, antitussive, anxiolytic, and treatment for opiate withdrawal).

  17. Singh D, Müller CP, Vicknasingam BK. Kratom (Mitragyna speciosa) dependence, withdrawal symptoms and craving in regular users. Drug Alcohol Depend 2014; 139: 132-7. PubMed Citation  (Survey of kratom abuse among 293 Malaysian men, who typically used it 3 times daily, to improve energy, treat pain or avoid opiate use; most were dependent and had a history of withdrawal symptoms if they tried to stop).

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  1. PubMed logoRecent References on Kratom

  2. Clinical Trials logoTrials on Kratom

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