Who Should Not Take Kratom

Is There an Official List?

No. The reason is worth knowing.

The two federal agencies that have looked hardest at kratom publish no caution list. The Food and Drug Administration warns consumers not to use kratom at all. It names three risks: liver toxicity, seizures and substance use disorder. The Drug Enforcement Administration states that kratom has no legitimate medical use in the United States.

Neither agency writes an exclusion list. An exclusion list implies that everyone not named on it is fine. That is not their position.

The lists that do exist come from clinical references written for doctors. One of them opens its section on the subject plainly. There’s little information about absolute contraindications for kratom.

So what follows comes from case reports and clinical references, not from an agency. It is the best that has been published. It is not complete, and nobody claims it is.

How Good Is the Evidence Behind These Warnings?

It varies, and we’re going to tell you where.

The FDA warns against kratom on three counts: liver toxicity, seizures and substance use disorder. The three do not rest on the same amount of work.

Liver Injury: What the Registry Actually Is

Liver injury has the strongest case behind it, and the way that case was built matters as much as the number it produced.

Start with what this evidence is not. Nobody gave anyone kratom. There was no trial. The U.S. Drug-Induced Liver Injury Network is a federally funded group of hospitals that has been enrolling patients who arrive with unexplained liver injury since 2003 and then working out, case by case, what caused it.

Enrollment is not a judgment call. A patient qualifies on laboratory thresholds: total bilirubin at or above 2.5 mg/dL or an INR above 1.5 alongside any enzyme elevation, or enzyme elevations above five times the upper limit of normal on two measurements at least a day apart. Every cause of liver injury that is not a drug or an herbal or dietary product is excluded before the case proceeds.

Cause is then assigned by structured expert consensus. Three liver specialists review the same case independently and then agree a grade on a five point scale: definite at greater than 95 percent likelihood, highly likely at 75 to 95 percent, probable at 50 to 74 percent, possible at 25 to 49 percent, and unlikely below 25 percent. The physician who has published on that process describes it as the most well established process of its kind for liver injury and, in the same paper, as an imperfect standard. Both halves of that are true and we are not going to quote only the first one.

The Eleven Cases

Between 2003 and 2019 the network enrolled 404 liver injury cases tied to herbal and dietary products. Eleven scored definite, highly likely or probable for kratom.

Put that against the size of the registry. Between 2004 and 2019 it enrolled 2,193 suspected liver injury cases and graded 1,950 of them for cause. Of those, 369, or 19 percent, were attributed to herbal and dietary products. The eleven kratom cases are roughly 3 percent of that group and about 1 percent of every graded case in the registry.

Here is who those eleven were. Nine were men. The median age was 40, with a range of 25 to 70. The median time on kratom before injury began was 14 days, ranging from 5 to 23. The median time from starting kratom to the first symptoms was also 14 days, ranging from 5 to 28, and laboratory abnormalities followed at a median of 21 days.

Here is what happened to them. All eleven turned yellow, with a median peak bilirubin of 11.7 mg/dL. Eight were admitted to hospital. Three developed features of liver failure. Nobody died and nobody needed a transplant. Ten had fully normal liver tests within six months, most improving quickly, and the eleventh had mildly raised tests that came back to normal at one year. The median time to full resolution was 90 days, with a range of 34 to 365.

That last paragraph is the one most often left out when these eleven cases are cited, in either direction. Severe and reversible are both accurate, and dropping either word misrepresents the finding.

What the Product Testing Did and Did Not Show

Researchers obtained three of the products those patients had taken. The National Center for Natural Products Research at the University of Mississippi analyzed them and found mitragynine and 7-hydroxymitragynine, with no other pharmaceutical adulterant, toxicant or contaminant.

Be precise about what that establishes. It establishes that those patients were taking real kratom rather than something spiked or contaminated, which rules out one alternative explanation. It does not identify a mechanism, it does not name a responsible constituent, and it does not tell anyone what caused the injury. Nobody has worked that out.

One Early Hint, and Nothing More

The same study sequenced immune system genes in those patients. Seven of the eight European American patients carried either HLA-B*57:01 or HLA-B*44:03. Both appeared at a frequency of 0.25 in this group against 0.04 and 0.05 in the general population.

The authors say plainly that the small sample limited what the genetic analysis could show. Eleven patients cannot establish a susceptibility marker. It is a hint worth following, and it is the only lead anyone has toward the question of who is at risk.

Eleven Is a Floor, Not a Total

That count includes only patients who reached a participating hospital, met the laboratory thresholds, and then cleared a three specialist review. Anyone who never sought care, was seen somewhere outside the network, or whose case could not be separated from another cause is not in it.

The NIH drug injury reference counts more. It records at least two dozen published cases of liver injury with jaundice, a similar number reported to the FDA adverse event database, and it grades kratom a likely cause.

The published case literature sits alongside both. A 2020 review gathered 26 published cases: 65 percent male, median age 32, median time to onset 22 days, and cholestasis commonly seen on biopsy. The presentations were jaundice, abdominal aching and other cholestatic symptoms.

Three of the network’s eleven were enrolled in its first decade. Eight came in the final three years. The authors read that as a signal that rising use is producing rising injury, and their closing line is that practitioners should be aware of the risk of severe liver injury.

One limitation on all of it, which we will state rather than leave for you to notice. That study covers cases through 2019. It is the best registry evidence that exists and it is also six years old, and the products on the market have changed since.

Seizures Rest on Far Less

A systematic review published in October 2025 searched the published literature. It also searched two federal adverse event databases. It found twenty patients in total. That’s across every qualifying case report and case series. Only one of the twenty had a measured level of kratom’s main alkaloid in his body. Half were taking other substances at the time. Several already had epilepsy or had undergone brain surgery. Nobody has worked out a mechanism by which kratom would trigger a seizure.

All four authors of that review are employed by a consulting firm. It concludes in the direction that favors the product. We use it for what it counted, never for what it concluded. Its conclusion appears nowhere on this page.

Substance Use Disorder Sits Between Them

The FDA says so itself. Its own page states that a well designed study of how habit-forming kratom is has not been run. The agency awarded a grant for one in September 2024.

We’re telling you this because it answers the question this page exists for. The gap is not that the warnings are overstated. The gap is that the work needed to say who is at risk has not been done. FDA puts kratom use in 2021 at an estimated 1.7 million Americans aged 12 and over. Set eleven rigorously confirmed liver injuries against a number that size. Something happens to some people. Nobody can yet say who.

That is not a reason to feel cleared. It is the reason this list cannot be read as complete.

Kratom During Pregnancy and Nursing

This is the one exclusion that appears in every published source.

A 2023 review gathered every published case of kratom use during pregnancy it could find. There were ten reports covering twelve mother and infant pairs. They came from the United States, Canada, Thailand and Switzerland. Nine of the twelve women had used kratom daily. Most had used it regularly for months before becoming pregnant.

Most were identified only after giving birth, when the baby began showing signs of withdrawal.

Ten of the newborns showed neonatal abstinence syndrome. That is the withdrawal syndrome seen in infants exposed before birth. Onset was day two on average, with a peak by day four. Seven of the ten were given morphine. It started around day two and ran five to ten days. Those infants went home between day twelve and day fourteen. One needed two months of weaning. Restricted growth before birth showed up in five of the reports.

The FDA states separately that it knows of cases of neonatal abstinence syndrome. It describes jitteriness, irritability and muscle stiffness in newborns.

That review’s author declares no conflicts of interest. It is worth saying out loud on a page that also cites a paper written by employees of a consulting firm.

What the review cannot do is tell you your odds. Twelve mother and infant pairs is a set of case reports, not a study of risk. The author noted that no early births, birth defects or fetal deaths turned up in the cases gathered. Ten case reports cannot show that those things do not happen.

All of that published work concerns exposure before birth. Say you’re pregnant, or think you may be, or are nursing. That’s a conversation to have with a doctor. It is not a call to make from a website.

Existing Liver, Kidney, Heart, Lung or Nerve Conditions

Clinical references tell people with these conditions to avoid kratom. The reason is that case reports describe harm to each of those organ systems.

Be clear about what that advice is. It is caution rather than measurement. An organ already under strain is a poor candidate for an added load nobody has studied. The same NIH reference records a 2020 review of eighty five reported cases of kratom liver injury. Those cases came from published papers, conference abstracts, FDA reports and internet sources. The review found the frequency, the risk factors, the mechanism and the best management all unclear.

Cautious is not the same as proven. It is also not the same as nothing. The people who see these injuries in hospitals write down who they’d tell to stay away. This is the list they write.

Kratom Side Effects covers what gets reported at the milder end. It also covers where the line sits between an effect and a reason to stop.

Anyone Taking Prescription Medication

This one is large enough to have its own page, and it has one.

Kratom alkaloids get in the way of enzyme systems the body uses to clear drugs. The clinical reference named earlier covers one of them. Mitragynine appears to block a clearance pathway called glucuronidation. Buprenorphine and ketamine are two of the drugs that depend on it. Blocking a clearance route means the other drug can build up rather than simply adding to what kratom does. Its own advice is plain. Anyone taking a drug cleared by that pathway should avoid kratom, or ask a clinician first.

Kratom Drug Interactions covers this in full. It includes what has actually been measured in humans. If you take anything on prescription, read that page rather than this paragraph.

One practical point belongs here. Kratom does not show up on a standard drug panel. A surgical team or an emergency crew will not find it unless somebody tells them. If you have surgery booked, say so beforehand.

A History of Substance Use Disorder

Clinical references name this directly, and it is the exclusion most likely to be argued with.

The reasoning runs like this. A history of using several substances is a known risk factor in kratom associated deaths. Kratom itself builds tolerance. It can lead to dependence. It brings a withdrawal syndrome when it stops. Someone with that history is being asked to handle a product carrying the same problem.

We will not soften this. Kratom is not an answer to anyone’s dependence on anything, and we never describe it that way. If dependence is the reason kratom is being considered, that’s a conversation for a doctor or an addiction specialist.

Is Kratom Addictive? and Kratom Withdrawal cover what regular use builds and what stopping is reported to involve. Kratom and Alcohol covers mixing. That’s where the serious outcomes gather.

Anyone Under 21

Whole Earth Gifts sells to adults 21 and over. Some states set a lower limit and some set none. Kratom Age Limit covers how that varies.

Our limit does not come from a study, because no study exists. The published work on kratom covers adults. Where nothing has been measured in young people, a lower limit is not the answer.

What If You Are Not On This List?

Then you’ve reached the end of an incomplete list. That’s a different thing from being cleared.

Everything above was built from case reports, adverse event databases and clinical references. None of those can tell one person their own risk. Only one item here has a forward looking study behind it. That item is liver injury. It is also the one where researchers say plainly that they cannot tell who is susceptible.

So the useful move is not to check yourself against a list. It is to write down what you take and what happens. That gives a doctor something real to work from. It also means you catch a change while it’s small. The printable kratom tracker sheets in our Responsible Use Toolkit are built for that.

Responsible Kratom Use covers the rest of what regular use carries and where each risk sits.