Kratom and concentrated 7-hydroxymitragynine products, commonly called 7-OH, have received growing attention because of concerns about dependence, opioid-like effects, withdrawal and overdose. New medical research is now drawing attention to another potential concern: breathing problems and lung complications associated with kratom, mitragynine and 7-OH exposure.
A systematic review published in the Journal of Medical Toxicology on August 27, 2026 examined previously reported pulmonary complications involving these substances. Researchers identified several patterns, including respiratory depression, acute respiratory distress syndrome (ARDS), pulmonary edema, diffuse alveolar hemorrhage and hypersensitivity-related lung inflammation.
However, these findings need to be interpreted carefully. The available evidence remains limited, and the researchers describe the proposed patterns as provisional and hypothesis-generating. The review does not establish that kratom or 7-OH directly causes every reported lung condition.
Still, the findings add another important dimension to the conversation surrounding concentrated kratom-derived products, particularly as Kentucky has established restrictions specifically addressing concentrated 7-OH.
For people in Louisville and throughout Kentucky, understanding how kratom and 7-OH may affect breathing, what warning signs may indicate an emergency and how concentrated products differ from traditional kratom is increasingly important.
Kratom comes from the leaves of Mitragyna speciosa, a tree native to Southeast Asia. Its leaves contain several naturally occurring alkaloids, with mitragynine generally being the most abundant.
One of its other alkaloids is 7-hydroxymitragynine, or 7-OH.
Although 7-OH occurs naturally in kratom at relatively low concentrations, concentrated products can contain substantially different concentrations than traditional plant material. Products marketed specifically for their 7-OH content may therefore present a different risk profile than conventional kratom leaf or powder.
This distinction has become increasingly important for consumers, clinicians and regulators.
Kentucky currently designates 7-hydroxymitragynine as a Schedule I controlled substance when it is concentrated above 400 parts per million on a dry-weight basis. The Kentucky regulation specifically states that this designation does not apply to mitragynine.
In other words, Kentucky’s approach distinguishes certain concentrated 7-OH products from mitragynine rather than treating every kratom product identically.
The August 2026 systematic review examined human case reports, conference abstracts and forensic or autopsy reports describing pulmonary outcomes following exposure to kratom, mitragynine or 7-OH.
Researchers identified 24 reports, including 14 clinical reports and 10 forensic reports.
Rather than treating every respiratory complication as the same phenomenon, researchers grouped the reported cases into five provisional categories.
These included:
These categories do not mean everyone who uses kratom or 7-OH will experience these conditions. They represent patterns identified in a relatively small collection of previously reported cases.
That distinction is important.
The researchers classified the relationship between exposure and the reported complications as probable in some cases, possible in others and unlikely in a small number. Pulmonary edema and congestion were also described as nonspecific findings.
The review therefore provides an important signal for further research rather than definitive proof of causation.
One of the most concerning findings involves central respiratory depression.
Respiratory depression occurs when breathing becomes abnormally slow, shallow or ineffective. This is particularly dangerous because inadequate breathing can prevent the body from receiving enough oxygen.
The new review identified central respiratory depression among the reported complications associated with kratom-related exposure.
This possibility is particularly relevant when discussing concentrated 7-OH because 7-OH interacts with opioid receptors.
Signs that someone may be experiencing dangerous respiratory depression can include:
Severe breathing problems should always be treated as a medical emergency.
Call 911 immediately if someone is unconscious, cannot be awakened or is breathing abnormally.
The systematic review also identified reports involving acute respiratory distress syndrome, commonly abbreviated ARDS, and other forms of acute lung injury.
ARDS is a serious condition in which inflammation and fluid accumulation interfere with the lungs’ ability to provide oxygen to the body.
Symptoms may include severe shortness of breath, rapid breathing, low oxygen levels and significant difficulty breathing.
ARDS can have many causes, including severe infections, aspiration, trauma and toxic exposures. Therefore, identifying kratom or 7-OH exposure in a patient does not automatically establish that the substance caused ARDS.
The researchers nevertheless suggest that clinicians consider kratom and 7-OH exposure when evaluating otherwise unexplained acute lung injury.
Pulmonary edema refers to abnormal fluid accumulation within the lungs.
The 2026 systematic review found pulmonary edema or congestion among forensic reports involving kratom-related exposure. However, the researchers specifically caution that pulmonary edema is a nonspecific finding.
Many different medical emergencies can cause fluid accumulation in the lungs.
For that reason, pulmonary edema identified after kratom exposure should not automatically be interpreted as proof that kratom caused the condition.
Instead, these reports contribute to a larger pattern that researchers believe deserves additional investigation.
Another uncommon but serious pulmonary condition identified in the review was diffuse alveolar hemorrhage.
This condition involves bleeding into the small air sacs of the lungs. Symptoms can include difficulty breathing, coughing, low oxygen levels and, in some cases, coughing up blood.
The systematic review identified three reports involving diffuse alveolar hemorrhage.
This remains an extremely limited body of evidence. Researchers are not suggesting that diffuse alveolar hemorrhage is a common consequence of kratom use.
Instead, its appearance in several reports provides another reason for clinicians to ask about kratom and concentrated 7-OH exposure when evaluating unexplained pulmonary symptoms.
Researchers also identified reports of eosinophilic or hypersensitivity pneumonitis.
These conditions involve inflammation within the lungs that can sometimes occur following exposure to medications, chemicals, environmental substances or other triggers.
Symptoms may include coughing, shortness of breath, fever, chest discomfort and low oxygen levels.
Only a small number of these cases were identified in the review, so substantially more research is needed before researchers can determine how frequently these reactions occur or whether particular kratom products increase the risk.
One of the most important distinctions for consumers is the difference between traditional kratom products and concentrated products marketed primarily for their 7-OH content.
7-OH is associated with opioid-receptor activity, and concentrated products can expose users to substantially different amounts than would normally occur in traditional kratom leaf.
The FDA has warned specifically about products containing concentrated 7-OH and has emphasized that these products should not simply be treated as equivalent to traditional kratom.
This distinction also appears in Kentucky’s regulatory framework.
Kentucky designates 7-OH above 400 parts per million on a dry-weight basis as Schedule I while explicitly excluding mitragynine from that designation.
For Kentucky residents, this makes understanding exactly what a product contains particularly important.
Substance combinations can make respiratory emergencies substantially more difficult to interpret and potentially more dangerous.
Someone using kratom or 7-OH may also consume alcohol, prescription medications, opioids, benzodiazepines or other substances.
When multiple substances capable of causing sedation are combined, the potential for severe impairment can increase.
Polysubstance exposure also makes it difficult to determine which substance caused a particular medical complication.
This is another reason the new systematic review should not be interpreted as proving that kratom caused every respiratory problem described in the underlying reports.
From a safety perspective, however, unexpected sedation or abnormal breathing after taking any psychoactive substance requires immediate attention.
Because 7-OH has opioid-like pharmacological activity, suspected overdose involving severe sedation or respiratory depression should be treated seriously.
If opioid overdose is suspected and naloxone is available, administering naloxone while calling 911 may be appropriate. Emergency medical evaluation remains necessary even if the person begins responding.
Naloxone should never be used as a reason to delay emergency care.
Someone who initially improves can experience additional complications or may have taken other substances that naloxone does not reverse.
Seek emergency medical help immediately if someone who has taken kratom, 7-OH or another substance:
When speaking with emergency responders, provide as much information as possible about what the person may have taken.
If product packaging is available, keep it for medical personnel. Concentrations and ingredients may vary considerably between products.
Kentucky has taken a targeted approach to concentrated 7-OH.
Under 902 KAR 55:015, 7-hydroxymitragynine concentrated above 400 parts per million on a dry-weight basis is designated as a Schedule I controlled substance.
The regulation explicitly states that the designation does not apply to mitragynine.
Kentucky also maintains separate requirements governing kratom processors, retailers and products.
Because laws and regulations can change, people should consult current Kentucky government resources rather than relying on product packaging, retailer claims or older online information when determining a product’s legal status.
Repeated exposure to substances with opioid-like effects can lead to tolerance, physical dependence and withdrawal in some people.
A person experiencing dependence may find that they need increasing amounts to achieve the desired effect or experience uncomfortable symptoms when attempting to stop.
Possible withdrawal symptoms associated with kratom-related dependence can include restlessness, irritability, anxiety, sleep problems, muscle discomfort, gastrointestinal symptoms and cravings.
The severity and duration of withdrawal can vary substantially depending on the product, concentration, amount used, frequency of use and whether other substances are involved.
Concentrated 7-OH products create additional concern because consumers may be exposed to much greater amounts of 7-OH than would naturally occur in traditional kratom.
Not everyone who uses kratom develops a substance use disorder. However, some people find themselves taking kratom or concentrated 7-OH more frequently than intended or continuing despite negative consequences.
Potential warning signs include increasing tolerance, unsuccessful attempts to stop, cravings, withdrawal symptoms, spending significant amounts of time obtaining or using the substance and continuing use despite physical, emotional, financial or relationship problems.
For someone experiencing these patterns, professional assessment can help determine whether treatment is appropriate.
Treatment should be individualized rather than based solely on the substance someone reports using.
The emerging research surrounding kratom and respiratory complications does not mean every person who has used kratom requires treatment. It does reinforce the importance of recognizing that kratom-derived products can have meaningful physiological effects, particularly when concentrated alkaloids such as 7-OH are involved.
At Louisville Addiction Center, treatment focuses on the person rather than simply the name of the substance.
An individualized assessment can help identify patterns of substance use, withdrawal concerns, co-occurring mental health needs, polysubstance use and other factors that may influence recovery.
Depending on clinical needs, ongoing treatment may include structured outpatient care, individual and group therapy, relapse-prevention planning, behavioral therapies, family support and continued recovery services.
If kratom, 7-OH, opioids or other substances have become difficult to stop, reaching out for an assessment can help clarify the appropriate next step.
Respiratory depression has been reported following kratom-related exposure and was one of the patterns identified in a 2026 systematic review. However, the available evidence remains limited, and individual risk may depend on the product, concentration, amount consumed and other substances involved.
7-OH has opioid-like activity, and respiratory depression is a concern with substances that significantly affect opioid receptors. Severe sedation, slow breathing or inability to wake someone should be treated as a medical emergency.
Researchers have reported several pulmonary complications following kratom-related exposure, including acute lung injury, ARDS, diffuse alveolar hemorrhage and hypersensitivity-type inflammation. Current evidence does not establish that kratom directly causes every reported condition, and more research is necessary.
No. 7-hydroxymitragynine is an alkaloid associated with kratom, but concentrated 7-OH products can contain substantially different concentrations than traditional kratom leaf. Regulators increasingly distinguish concentrated 7-OH products from conventional kratom.
Kentucky designates 7-hydroxymitragynine concentrated above 400 parts per million on a dry-weight basis as a Schedule I controlled substance. The regulation specifically states that this designation does not apply to mitragynine.
Because 7-OH has opioid-like activity, naloxone may be appropriate when opioid-type overdose is suspected. Call 911 immediately for severe respiratory depression or unconsciousness, administer naloxone if available and follow emergency-dispatch instructions.
Call 911 for severe shortness of breath, unconsciousness, inability to wake someone, stopped or abnormally slow breathing, blue or gray lips, coughing up blood or other signs of severe medical distress.
Repeated use of products with opioid-like effects may result in tolerance, dependence, withdrawal and compulsive use. Anyone struggling to reduce or stop 7-OH use can seek a professional substance-use assessment.
The August 2026 systematic review provides an important new perspective on the potential health effects associated with kratom, mitragynine and 7-OH.
Researchers identified patterns involving respiratory depression, acute lung injury, pulmonary edema, diffuse alveolar hemorrhage and hypersensitivity-related lung inflammation.
But the evidence should not be overstated.
The review was based on a relatively small collection of clinical and forensic reports, and its authors characterize the proposed pulmonary categories as provisional and hypothesis-generating. Additional research will be necessary to determine how frequently these complications occur, which products present the greatest risk and how factors such as dose, concentration and polysubstance use influence outcomes.
For Kentucky residents, the distinction between traditional kratom and concentrated 7-OH is especially relevant because state regulations specifically control 7-OH above a defined concentration.
If you or someone you care about is struggling with kratom, concentrated 7-OH, opioids or other substances, Louisville Addiction Center can help you understand your treatment options and determine an appropriate level of care.
If someone is experiencing severe breathing problems, unconsciousness or a suspected overdose, call 911 immediately.
Kanchustambham V, Saladi S. Kratom-Associated Pulmonary Toxicity: A Systematic Review of Case Reports and Forensic Series with a Proposed Clinical Phenotype Classification. Journal of Medical Toxicology. Published August 27, 2026.
Kentucky Cabinet for Health and Family Services. 902 KAR 55:015: Schedule I Controlled Substances.
Kentucky General Assembly. KRS Chapter 217: Kratom Extracts and Products.
U.S. Food and Drug Administration. Hiding in Plain Sight: 7-OH Products.
U.S. Drug Enforcement Administration. DEA to Temporarily Schedule 7-OH and Related Substances to Protect Public Safety. July 1, 2026.
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