The Truth About CHS: Rare Condition, Rampant Misdiagnosis, and Media Hysteria

If you’ve noticed an uptick in media hysteria over the rare condition known as cannabis hyperemesis syndrome (CHS) as of late, you’re not alone. You’re also not alone when it comes to having a healthy dose of suspicion when it comes to articles that sensationalize or misinterpret the potential effects of cannabis use.

As cannabis legalization expands across the United States, reports of CHS have surged across news outlets and social platforms. MedicateOH/MedicateKY sorts out the information to help patients and consumers make thoughtful decisions:

What is Cannabis Hyperemesis Syndrome (CHS)?

Hyperemesis (from “hyper-” meaning excessive and “emesis” meaning vomiting) refers to severe, persistent nausea and vomiting and is a medical term that exists outside of its relationship to cannabis. The Cleveland Clinic describes CHS as a condition that “happens when you have cycles of nausea, vomiting and abdominal pain after using cannabis (marijuana) for a long time.”

But according to clinicians and researchers who study the condition, CHS remains rare, difficult to diagnose, and widely misunderstood. Dr. Kennon Heard, professor of Emergency Medicine at the University of Colorado School of Medicine and chief of that department’s medical toxicology section calls it the “leading cause of marijuana-related ER visits”.

How common is CHS?

But how common CHS actually is is hard to say, according to Heard. That’s in part because there’s no diagnostic code for cannabinoid hyperemesis syndrome. When patients are discharged from an emergency department, the official diagnosis is typically “vomiting,” though the CHS details are entered into the medical record’s notes.

A 2022 survey found that more than 4.5 million 18- to 25-year-olds use cannabis daily or near daily, with 81% meeting the “criteria” for cannabis-use disorder (CUD). The survey notes that despite more people using cannabis since legalization, the prevalence of adult CUD was relatively stable between 2002 and 2014. US estimates around 16-18 million diagnosed with CUD in a given year (as of 2021), while globally, 3.7 million new cases emerged in 2019.

CUD was added to the DSM-5 in 2013, combining previous abuse and dependence categories into one disorder and adding craving as a criterion. CUD is defined as “cannabis use leading to significant impairment or distress, characterized by continued use despite negative impacts on health, work, or relationships, and includes symptoms like strong cravings, tolerance, withdrawal (anxiety, sleep issues, irritability), and unsuccessful attempts to cut down use”.

CHS is not CUD, although the two conditions can be related. CHS was first identified in 2004 in Australia. In this cross-sectional study of US emergency room visits, CHS reports increased sharply during the COVID-19 pandemic and has remained elevated since.

What clinicians currently know about CHS

The Cleveland Clinic says CHS typically appears in waves, and some patients report temporary relief from hot showers. The Clinic also notes that no biological mechanism has been identified, and the condition itself remains poorly understood. While hot showers or baths were thought to be a marker of CHS, “that doesn’t seem quite as universal as we initially thought it was,” admits Heard.

Researchers at the National Institutes of Health have pointed out that most published CHS studies rely on small case reports or retrospective chart reviews. CHS is diagnosed only after other gastrointestinal conditions have been ruled out, because there is no test that can confirm it. This makes CHS vulnerable to being confused with disorders that look identical.

Researchers do know that cannabis, when inhaled or consumed, affects multiple organs, primarily the brain and lungs through direct interaction with the central nervous system and inhalation. It also impacts the liver through metabolism and can affect the cardiovascular system, gastrointestinal system, and reproductive system. When cannabis enters the body, it responds to your endocannabinoid system’s receptors and goes to work to achieve a balance (homeostasis). It’s most well-studied component, THC (tetrahydrocannabinol), mimics anandamide, a natural cannabinoid your body produces. THC activates CB-1 receptors in the brain, triggering the release of dopamine and altering communication between neurons.

Experts: Cannabis Can’t Kill You

It is widely accepted in the medical community that a fatal overdose from cannabis toxicity alone is impossible. There are no confirmed cases of adults dying solely from consuming too much THC. The vast majority of deaths where cannabis is detected also involve other drugs (e.g., alcohol, opioids, cocaine), making it impossible to attribute the death to cannabis.

Studies that examine historical cannabis use records aren’t able to show a causal effect of cannabis. Links between cannabis use and outcomes like psychosis or poor school performance don’t prove cannabis causes them. Other factors like genetics, family environment, or other drugs could influence both cannabis use and the outcome, making the relationship complex and requiring more rigorous study designs to determine true causality.

Logically speaking, if there’s not enough evidence to definitively know the benefits of cannabis, there’s isn’t enough evidence to know its harms either.

Why CHS is often misdiagnosed

Emergency physicians say misdiagnosis is increasingly common. A gastroenterologist writing in STAT News reported that some patients were labeled with CHS simply because they disclosed cannabis use, even when other gastrointestinal issues had not been evaluated. As a result, patients with conditions like cyclic vomiting syndrome or gallbladder disease are sometimes told cannabis is causing their symptoms when that may not be the case.

Researchers writing in JAMA Network also found that earlier hospital statistics on CHS were inflated. They reported that hospitals often combined diagnostic codes for cannabis use and vomiting, even when clinical notes did not confirm CHS. This coding practice made it appear as if CHS was more common than it actually was.

Conditions that mimic CHS include cyclic vomiting syndrome, gastroparesis, alcohol-related gastritis, and anxiety-induced vomiting. These conditions can present nearly identically in the ER. Without a biomarker or diagnostic test, separating these conditions from CHS remains challenging.

Other Reasons Cannabis Could Be Making People Sick

Clinicians and toxicologists say a variety of factors can cause cannabis users to feel ill, and most have nothing to do with Cannabinoid Hyperemesis Syndrome. These issues range from product contamination to interactions with alcohol or other drugs, as well as the effects of high-potency concentrates.

Contamination from pesticides or solvents
State testing requirements vary widely, and products in unregulated or poorly regulated markets may contain pesticides, mold, or residual solvents. According to state lab directors, even trace amounts of certain fungicides or insecticides can irritate the stomach or cause acute nausea. Residual butane, propane, or other solvents in improperly purged concentrates can also trigger headaches, vomiting, and dizziness.

Why scientific understanding remains limited

Medical researchers say several factors limit what is known about CHS. No validated biological marker exists, and no large, long-term study has tracked cannabis users to determine how often CHS actually occurs. Cannabis products also vary significantly in potency and formulation, making comparisons across patients difficult.

Published cases also vary widely in severity and symptom patterns. Some patients report daily vomiting, while others describe intermittent episodes months apart. This variability makes it harder for clinicians to establish a consistent diagnostic picture.

How media coverage shapes public perception

Media reporting has contributed heavily to the public’s misunderstanding of CHS, especially in recent weeks. Some outlets use dramatic language that does not reflect clinical practice. For example, a widely shared People Magazine article popularized the slang term “scromiting” (screaming while vomiting) though medical experts note that the term does not appear in any clinical guidelines or peer-reviewed literature.

Other recent news stories have reported sharp increases in CHS without acknowledging factors that might influence these numbers, such as expanded awareness among the medical community or improved reporting procedures. Public health researchers say these nuances are essential for understanding whether CHS is truly increasing or simply being identified more often.

The broader context

Cannabis is no stranger to political propaganda, especially when framed by those who stand to lose money from it. Alcohol and pharmaceutical industries have historically financed campaigns to shape public opinion about cannabis. For instance, Insys Therapeutics, a manufacturer of a synthetic fentanyl spray, donated half a million dollars to a campaign opposing cannabis legalization in Arizona in 2016. Purdue Pharma and Abbott Laboratories (makers of OxyContin and Vicodin, respectively) were among the top contributors to the Anti-Drug Coalition of America and the Partnership for Drug-Free Kids, organizations that historically opposed legalization.

While there is no direct evidence linking industry funding to recent CHS coverage, analysts say this context makes it necessary to interpret emerging claims carefully.

What current data say about prevalence

Despite the increase in media attention, CHS appears to account for a small share of cannabis-related medical visits. Emergency physicians interviewed for clinical reviews report that most cannabis-related ER visits involve anxiety, intoxication, or dehydration, not CHS.

Clinicians at the Cleveland Clinic say cannabis-related gastrointestinal symptoms “almost never” require intensive medical intervention. Dehydration, they note, is the most common issue requiring treatment — typically with fluids and rest.

Recommendations for cannabis consumers

MMJ doctors and dispensary budtenders suggest consistent, controlled dosing approaches. Tinctures, capsules, and balanced THC:CBD products tend to deliver more predictable effects than smoked or vaporized products and can make it easier for patients to monitor their response over time.

While CHS is characterized by heavy, chronic cannabis use, it’s still important to note the age-old advice of “start low, go slow” especially when dosing edibles. Eating a meal high in fat and drinking plenty of water while consuming cannabis are also good practices, especially for those using THC-rich edibles or concentrates. Unintentional cannabis overdoses cam typically be reversed with CBD isolate, peppercorns, food, and most importantly, time.

Cannabis overdoses are not emergencies, typically. Emergency rooms visits should be reserved for life-threatening issues like severe chest pain, difficulty breathing, major trauma (uncontrolled bleeding, serious burns, major head injury with confusion/seizures), stroke/heart attack signs, or severe allergic reactions. Because THC can contribute to anxiety and paranoia, users sometimes overthink their symptoms and seek medical attention unnecessarily in the overabundance of caution. When in doubt, call the ER ahead of time for guidance on whether you need to be seen in person or not.

Where research needs to go next

Another factor contributing to concerns about CHS misdiagnosis is the broad and nonspecific nature of its reported symptoms. Episodes of nausea, vomiting, and abdominal pain are common across numerous medical conditions, and emergency physicians often have only minutes to make a preliminary assessment. According to clinicians who study gastrointestinal disorders, symptoms attributed to CHS overlap with cyclic vomiting syndrome, cannabinoid withdrawal, foodborne illness, gallbladder disease, and even anxiety-related gastrointestinal distress. Without a definitive lab test for CHS, doctors have to rely on patient history, which is often incomplete or inconsistent.

Physicians have noted that the tendency to diagnose CHS has increased sharply as awareness of the condition spreads. According to emergency medicine doctors quoted in recent reporting, some hospitals have begun adding CHS to their default list of suspected causes when a patient discloses cannabis use, even when other causes have not been ruled out. This shift, they say, risks anchoring bias—a well-documented diagnostic issue where the first suspected cause disproportionately influences the final diagnosis.

Some gastroenterologists also caution that the “hot shower relief” symptom, widely cited as central to CHS, is not specific to cannabis-related illness. Patients experiencing severe nausea from unrelated causes sometimes report the same temporary relief. As a result, attaching too much weight to this detail can steer medical professionals away from exploring more likely explanations.

Where’s the Emergency?

Additionally, public health data does not currently show the kind of widespread emergency complications that would be expected if CHS were as common as some headlines suggest. Emergency room visits linked to cannabis remain comparatively low and are often tied to high-THC edible overconsumption rather than chronic vomiting syndromes. Several researchers have argued that the increase in reported CHS cases may reflect increased awareness among health professionals rather than a true rise in incidence, creating a feedback loop where the more the condition is named, the more frequently it is used as an explanation.

Together, these factors suggest that a significant portion of CHS diagnoses may stem from a combination of overlapping symptoms, time-pressured triage, and a lack of clear diagnostic tools. As more physicians call for standardized criteria and controlled studies, the medical community continues to emphasize the need for caution in labeling cannabis as the cause before other possibilities are fully evaluated.

Moving forward

Researchers say progress in proper diagnosis will rely on establishing consistent criteria, conducting long-term prospective studies, identifying possible biomarkers, and improving hospital reporting accuracy. These steps would help distinguish true CHS cases from the many look-alike conditions that complicate diagnosis.

CHS is currently recognized in Western medicine as a legitimate condition, but evidence shows it is rare, frequently misdiagnosed, and still not fully understood. As cannabis use grows and public awareness increases, clinicians and researchers agree that clearer standards and better research will be key to ensuring accurate diagnoses and informed public discussion.

Have your own experience with CHS to share? Reach out and tell us your story.

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