Recognize Warning Signs, Understand the Research & Get Support

Americans for Safe Access created these educational resources to provide patients and medical professionals with accurate information about Cannabinoid Hyperemesis Syndrome (CHS). Since CHS was first recognized as a medical condition, it has been met with widespread skepticism from many cannabis advocates. Decades of misinformation about the dangers of cannabis, combined with the lack of definitive diagnostic tools, inconsistent case reporting, and sensational media coverage of the condition, have fueled mistrust. Unfortunately, this skepticism is preventing important CHS education, including information about early detection, from reaching patients and cannabis consumers.

It is true that we do not understand exactly why some people develop CHS from cannabis use, but there is no denying the growing number of people visiting emergency rooms across the United States with severe and recurring vomiting, abdominal pain, dehydration, and other complications. As researchers work to uncover the underlying causes of CHS and develop better diagnostic tools and treatments, it is only natural for cannabis advocates to develop hypotheses about the internal mechanisms that may be causing the condition. It is not acceptable to withhold information from patients and consumers about warning signs and symptoms, and it is definitely not okay to bully or harass people who are surviving and recovering from CHS.

 

SECTION 1: IDENTIFYING THE CONDITION

WHAT WE KNOW ABOUT CHS

Cannabinoid Hyperemesis Syndrome, or CHS, is a gastrointestinal condition associated with frequent, long-term cannabis use. It can cause recurring episodes of severe nausea, vomiting, abdominal pain, and dehydration. People may feel much better or have no symptoms between episodes.

CHS can be difficult to recognize because severe vomiting has many possible causes, early symptoms may be subtle, and there is no single laboratory test that confirms the condition. Only some people who frequently consume cannabis develop CHS, and researchers are still working to understand why some people are more susceptible than others.

WHAT DOES CHS LOOK LIKE?

CHS often involves cyclical episodes. Early symptoms may appear before severe vomiting begins and may be worse in the morning. Patients sometimes recognize a recurring pattern before their healthcare professionals do. Keeping track of when symptoms begin, how long they last, what time of day they are worse, periods when symptoms improve, and changes in cannabis consumption can provide useful information to a healthcare professional.

Healthcare sources describe CHS in three phases.

Prodromal Phase

The early phase may last for months or years and may include:

  • Morning nausea
  • Abdominal cramping or pain
  • Gagging
  • Appetite changes or feeling full quickly
  • Heartburn or indigestion
  • Diarrhea or constipation
  • Anxiety or fear of vomiting

Some patients increase their cannabis consumption during this phase because cannabis has previously helped them manage nausea, pain, sleep problems, appetite changes, or other symptoms. This can make the pattern harder to recognize.
 

Hyperemetic Phase

This phase can involve intense, recurring nausea and vomiting, abdominal pain, reduced food and fluid intake, weight loss, and dehydration. Severe or prolonged vomiting can cause electrolyte problems and acute kidney injury and may require emergency treatment or hospitalization. While many of the symptoms can be treated, this phase will not end without cannabis cessation.
 

Recovery Phase

Symptoms improve after cannabis is stopped, but recovery is not always immediate. Normal appetite and bowel function may take longer to return. Symptoms can recur if cannabis consumption resumes.

 

WHO DEVELOPS CHS?

CHS is most strongly associated with frequent and long-term cannabis exposure, but there is no single amount, product, or duration that determines who will develop it. JAMA patient guidance describes heavy cannabis consumption, typically daily or multiple times per day for more than one year, as a common risk pattern. Cedars-Sinai notes that many patients have consumed cannabis regularly for several years before symptoms appear.

Not everyone who consumes cannabis frequently develops CHS. The exact prevalence and the reasons for individual susceptibility remain uncertain.

SECTION 2 DIAGNOSIS, TREATMENT & RECOVERY

HOW IS CHS DIAGNOSED?

No single symptom or laboratory test confirms CHS. Diagnosis requires careful consideration of the patient’s history and other possible causes of nausea and vomiting.

A medical evaluation may include:

  • A detailed history of cannabis consumption and symptoms
  • Evaluation for other causes of vomiting and abdominal pain
  • Blood tests, electrolyte testing, urine testing, imaging, or other testing when clinically appropriate
  • Attention to the timing and recurrence of symptoms
  • Follow up after sustained cannabis cessation to determine whether symptoms resolve

CHS can be missed, but it can also be blamed too quickly when someone who consumes cannabis experiences vomiting. Cannabis consumption should be part of the clinical history, not a substitute for an appropriate medical evaluation.

The Hot Bathing Connection

Many people with CHS report temporary relief from hot showers or baths. Some people may spend long periods bathing during an episode, while others experience little or no relief.

Hot water can also reduce symptoms in other vomiting disorders, so relief from hot bathing does not by itself diagnose CHS. Hot bathing does not treat the underlying condition, and prolonged exposure to very hot water can contribute to burns or dehydration.

WHEN IS CHS AN EMERGENCY?

Repeated vomiting can lead to dehydration, electrolyte abnormalities, acute kidney injury, and other complications.

Seek medical care if:

Repeated vomiting makes it difficult or impossible to keep fluids down
You are urinating very little
You feel markedly dizzy
Abdominal pain is severe or worsening

Seek emergency help for:

Fainting, confusion, or collapse
Blood in vomit

JAMA also notes that rare, severe complications can include heart rhythm abnormalities, kidney failure, seizures, and death.

TREATMENT DURING A SEVERE EPISODE

Treatment depends on the patient and symptom severity. In emergency or hospital settings, care may include intravenous fluids, correction of electrolyte problems, and medications to control nausea and vomiting. Some clinicians may also use topical capsaicin or other medications in selected patients.

Patients should not attempt to self-treat a severe episode without appropriate medical evaluation, particularly when vomiting is persistent, or dehydration is developing.

RECOVERY TAKES TIME

Complete cessation of cannabis is currently the most effective long-term treatment for CHS. Symptoms do not necessarily disappear immediately after cannabis is stopped. Recovery can take time, and ongoing, prolonged, or worsening symptoms should be medically reassessed.

A short break followed by continued symptoms does not necessarily rule out CHS. Patients need realistic information about recovery and appropriate follow-up with a healthcare professional.

SUPPORT SHOULD NOT END WITH STOPPING CANNABIS

For many medical cannabis patients, cannabis was being consumed to address pain, nausea, sleep problems, appetite loss, anxiety, or another health concern. Those underlying needs still deserve treatment if CHS is suspected or diagnosed.

A CHS care and recovery plan may need to address:

  • The medical condition or symptoms for which cannabis was being consumed
  • Alternative treatment options
  • Emotional dependency or difficulty stopping cannabis
  • Follow-up with healthcare professionals
  • Support from family, friends, caregivers, and people with lived experience of CHS

People experiencing CHS deserve accurate information, careful diagnosis, appropriate treatment, and support without stigma.

SECTION 3 EVIDENCE & ONGOING RESEARCH

CHS RESEARCH &  RECOGNITION TIMELINE

2004: CHS is first described in the medical literature.

Cannabinoid Hyperemesis: Cyclical Hyperemesis in Association with Chronic Cannabis Abuse in Gut, a case series documenting nine patients with chronic cannabis consumption and cyclical vomiting. Seven of the nine stopped cannabis consumption and experienced resolution of the cyclical vomiting illness. Three patients who later resumed cannabis experienced a return of symptoms. This publication is generally recognized as the first medical description of what became known as CHS.

2012: A larger case series helps define the clinical picture of CHS.

Cannabinoid Hyperemesis: A Case Series of 98 Patients in Mayo Clinic Proceedings examined 98 patients with cannabinoid hyperemesis. The study documented common patterns including abdominal pain, frequent cannabis consumption, and relief from hot showers or baths, and proposed major and supportive criteria for recognizing CHS.

2017: A systematic review shows substantial growth in CHS research.

Cannabinoid Hyperemesis Syndrome: Diagnosis, Pathophysiology, and Treatment: A Systematic Review reviewed the growing CHS literature and included 170 CHS-related articles published through September 2015. The review found that most available evidence consisted of case reports, case series, and observational studies, highlighting both growing recognition of CHS and the need for stronger research.

2016 to 2022: Emergency department visits associated with suspected CHS increased substantially.

Cannabinoid Hyperemesis Syndrome, 2016 to 2022 used national emergency department data and identified approximately 113,700 CHS proxy visits during the study period. Because there was no CHS-specific diagnosis code at the time, researchers identified possible cases using combinations of vomiting and cannabis related diagnoses. These figures represent emergency department visits, not individual patients, and one person may have multiple visits.

2025: A treatment review highlights how much remains unknown about treating CHS.

Treatment of Cannabinoid Hyperemesis Syndrome: A Systematic Review and Treatment Algorithm for Consultation Liaison Psychiatrists identified 34 publications describing 63 individual CHS cases with patient-level treatment information. The review illustrates that although the overall CHS literature has grown, evidence about which treatments work best during an acute episode remains limited.

October  2025: CHS receives a diagnosis code.

The new ICD 10 CM code R11.16, Cannabis hyperemesis syndrome, took effect, giving healthcare professionals and researchers a specific code for documenting CHS. Before this, possible cases were often identified using combinations of vomiting and cannabis related diagnosis codes. The new code should improve CHS tracking and research, but increases in reported cases after its adoption may partly reflect better recognition and coding.

2026: Studies expand understanding and tracking of CHS.


Cannabinoid Hyperemesis Syndrome-A Survey-Based Approach to Understanding Symptoms and Cannabis Use Patterns surveyed 1,134 adults who reported a CHS diagnosis or similar symptoms. The study documented patterns in early symptoms, frequency and duration of cannabis consumption, product types, and other patient experiences. Because the survey relied on self-reported information and diagnoses were not independently confirmed, it does not establish how common CHS is or what causes it, but it provides one of the largest collections of patient-reported CHS data to date.

CDC also published Trends in Emergency Department Visits Involving Cannabis Hyperemesis Syndrome Identified Using a New Diagnosis Code — United States, January 2023–May 2026, identifying 199,565 emergency department visits involving CHS. The analysis found a substantial increase in identified CHS visits after the new diagnosis code took effect in October 2025, while cautioning that improved recognition and coding likely account for at least part of the increase. These figures represent emergency department visits, not individual patients, so one person may be counted more than once.

WHAT RECENT RESEARCH TELLS US

A 2026 study, Cannabinoid Hyperemesis Syndrome-A Survey-Based Approach to Understanding Symptoms and Cannabis Use Patterns, included an anonymous survey of 1,134 adults who reported a CHS diagnosis or similar symptoms. Participants described their cannabis consumption, symptoms, and experiences.

Among participants:

 

96.5% reported consuming cannabis at least daily

45% reported consuming cannabis six or more times per day around the time symptoms developed

65.4% reported more than three years of cannabis consumption before symptoms began

61.9% reported obtaining cannabis from licensed dispensaries

Symptoms were reported across flower, vape products, concentrates, edibles, and other forms of cannabis. Early symptoms most often included nausea and stomach pain and frequently clustered in the morning

The study provides useful information about patterns among respondents, but it does not establish how common CHS is in the general population or prove what causes the condition. Participation was voluntary, information was self-reported, and researchers did not independently confirm diagnoses.

What Researchers Still Do Not Understand About CHS

Researchers agree that cannabis exposure is central to CHS, but there is still no single accepted biological explanation for why CHS develops or why it affects some people who consume cannabis frequently while most do not. The pattern of symptoms improving after cannabis cessation and returning in some patients who resume cannabis provides strong evidence for a connection, but it does not tell us exactly what is happening inside the body.

One leading area of research is the endocannabinoid system, or ECS. The ECS helps regulate nausea and vomiting, gastrointestinal function, appetite, pain, stress responses, sleep, and body temperature. THC interacts with this system primarily through cannabinoid receptors. Researchers are investigating whether repeated exposure to THC over long periods may alter cannabinoid receptor signaling or disrupt normal ECS regulation in susceptible individuals. This could help explain one of the most puzzling features of CHS: cannabis can suppress nausea and vomiting for many people, yet chronic exposure is associated with severe vomiting in people who develop CHS. The mechanisms behind this paradox remain unclear.

Researchers are also studying the relationship between CHS and the digestive system. Cannabinoid receptors are present throughout the gastrointestinal tract, and cannabinoids can affect stomach emptying, intestinal movement, appetite, and communication between the digestive system and the brain. Changes in these processes could contribute to nausea, abdominal pain, and vomiting, but researchers have not determined whether any one of them is the primary cause of CHS.

The temporary relief some patients experience from hot showers or baths has provided another clue. Researchers have examined whether CHS involves systems that regulate body temperature, pain, and nausea, including cannabinoid receptors and TRPV1 receptors. Capsaicin, which activates TRPV1 receptors, is sometimes used to help manage symptoms during acute episodes. These observations may help researchers understand the pathways involved in CHS, but they have not established its underlying cause.

Stress and individual susceptibility may also matter. Patients report that stress, sleep disruption, alcohol, diet, menstrual factors, and other circumstances can sometimes worsen symptoms. Researchers are studying whether differences in genetics, metabolism, hormone and stress responses, underlying health conditions, nutrition, ECS function, or patterns of cannabis exposure help explain why one person develops CHS while another person with similar cannabis exposure does not.

Another unanswered question is whether dose, potency, product type, or route of administration changes a person’s risk. CHS has been reported among people consuming flower, concentrates, vape products, edibles, and other cannabis products and among people obtaining cannabis from both regulated and unregulated sources.

These unanswered questions matter, but they do not mean nothing is known about CHS. A recognizable clinical pattern has been documented for more than two decades, symptoms often improve with sustained cannabis cessation, and recurrence after cannabis is resumed has been reported repeatedly in the medical literature. At the same time, the absence of a definitive laboratory test or a complete understanding of the mechanism means that CHS should be diagnosed carefully. Cannabis exposure is an important part of the clinical history, but it should not replace an appropriate evaluation for other causes of persistent or recurring vomiting.

Understanding why CHS happens, why only some people develop it, and whether individual factors can predict susceptibility are among the most important questions for future CHS research.

 

SECTION 4 QUESTIONS & CONCERNS

Addressing Skepticism in the Cannabis Community

Skepticism about CHS often comes from real concerns. Patients and advocates have seen cannabis safety issues exaggerated, used to justify stigma, or discussed without acknowledging why people consume cannabis in the first place. Many patients also know that cannabis can relieve nausea, so CHS can sound contradictory.

At the same time, patient reports, clinical literature, emergency department data, and improvement after cannabis cessation show that CHS cannot be dismissed. The right response is not denial or panic. The right response is better education, better research, better clinical training, and better patient support.

Why Case Numbers Can Look Inconsistent

CHS case numbers vary widely across studies and public reports because researchers and healthcare systems are often measuring different things.

Some estimates are based on emergency department visits, not individual patients. One person with severe CHS may return to the emergency department multiple times, which can increase visit counts without representing the same number of unique individuals. Other people may experience CHS symptoms but never seek emergency care, may be treated in urgent care or primary care, or may never receive a CHS diagnosis.

Until October 2025, the United States had no CHS-specific ICD-10-CM diagnosis code. Studies often relied on combinations of vomiting and cannabis related diagnosis codes, which could miss cases or include cases that were not truly CHS. Even with the new code, counts depend on whether clinicians recognize CHS, ask about cannabis consumption, document it accurately, and apply the code.

This is why CHS numbers should be read carefully. An increase in recorded cases may reflect more CHS, better recognition, better coding, changes in cannabis use patterns, more frequent emergency department use, or some combination of these factors.

How Can Cannabis Relieve Nausea & Also Be Associated With CHS?

Cannabis can relieve nausea for many people, which can make CHS seem contradictory. THC and other cannabinoids affect systems in both the brain and digestive tract that are involved in nausea, vomiting, digestion, and stomach emptying. With repeated exposure, those systems may respond differently in susceptible individuals.

The exact biological mechanism of CHS remains uncertain. Improvement after stopping cannabis and recurrence after resuming it support the connection between cannabis exposure and CHS, but researchers are still studying why only some people develop the condition.

What About Contaminants or “Bad Weed”?

Cannabis contaminants can cause health problems, and product safety matters. However, CHS has been reported among people obtaining cannabis from licensed dispensaries, unlicensed sources, and home cultivation. In the 2026 Peterson study, the source of cannabis did not appear to change the pattern of CHS symptoms.

Switching products or cannabis sources is not an established treatment for CHS.

Is CHS Related to Diet & Nutrition?

Researchers have not established that CHS is caused by a particular food, diet, or nutritional deficiency. The strongest association remains frequent, long-term cannabis exposure in people who appear to be susceptible to the condition, while researchers continue to investigate the biological mechanisms that cause CHS. Cannabis cessation remains the most consistently supported long-term approach to resolving the condition.

The endocannabinoid system, or ECS, is likely involved in CHS. The ECS helps regulate nausea and vomiting, gastrointestinal function, appetite, stress, pain, sleep, and other physiological processes. Researchers have proposed that repeated cannabis exposure may alter cannabinoid receptor signaling or other aspects of ECS function in susceptible individuals, potentially helping explain the paradox of cannabis relieving nausea in many people while being associated with severe vomiting in people with CHS. However, the precise mechanisms remain uncertain.

Nutrition may also be relevant because the ECS is a lipid-based signaling system whose function is influenced by nutrient availability and dietary fatty acids. Endocannabinoids such as anandamide and 2-AG are synthesized from fatty acid precursors, and research has shown that dietary fatty acid intake can influence endocannabinoid levels and signaling. This does not mean that poor nutrition causes CHS or that changing a person’s diet can prevent or treat the condition, but it provides an important reason to study the relationship between nutrition, ECS function, and individual susceptibility to CHS.

Diet has also emerged as a question from people experiencing CHS. In the survey by Peterson and colleagues of 1,134 adults reporting a CHS diagnosis or similar symptoms, participants identified diet, along with stress, sleep disruption, alcohol, menstrual factors, and other factors, as potentially worsening symptoms. The researchers cautioned, however, that no research has established a CHS “foods to avoid” list.

 

SECTION 5 REFERENCES & PATIENT SUPPORT

SOURCES

  1. Angulo MI. Cannabinoid Hyperemesis Syndrome. JAMA. 2024;332(17):1496. doi:10.1001/jama.2024.9716. https://jamanetwork.com/journals/jama/fullarticle/2824833

  2. Bisogno T, Maccarrone M. Endocannabinoid signaling and its regulation by nutrients. Biofactors. 2014;40(4):373 to 380. doi:10.1002/biof.1167. PMID: 2475339

  3. Cedars Sinai. Cannabis Hyperemesis Syndrome (CHS). https://www.cedars-sinai.org/health-topics/cannabis-hyperemesis-syndrome-chs

  4. Peterson C, Simonian J, Mbengue M, Higgins J, Kirk R, Nava K, Lacinski R, Nelson A. Cannabinoid Hyperemesis Syndrome A Survey Based Approach to Understanding Symptoms and Cannabis Use Patterns. Cannabis Cannabinoid Res. 2026;11(4):335 to 347. doi:10.1177/25785125261421434. PMID: 41783912.

  5. Allen JH, de Moore GM, Heddle R, Twartz JC. Cannabinoid hyperemesis: cyclical hyperemesis in association with chronic cannabis abuse. Gut. 2004;53(11):1566 to 1570. doi:10.1136/gut.2003.036350.

  6. Vivolo Kantor AM, Liu S, Tanz LJ, Mattson CL, Schier J. Trends in Emergency Department Visits Involving Cannabis Hyperemesis Syndrome Identified Using a New Diagnosis Code, United States, January 2023 to May 2026. MMWR Morb Mortal Wkly Rep. 2026;75:391 to 396. doi:10.15585/mmwr.mm7530a2.

  7. Simonetto DA, Oxentenko AS, Herman ML, Szostek JH. Cannabinoid hyperemesis: a case series of 98 patients. Mayo Clin Proc. 2012;87(2):114 to 119. doi:10.1016/j.mayocp.2011.10.005. PMID: 22305024.

  8. Sorensen CJ, DeSanto K, Borgelt L, Phillips KT, Monte AA. Cannabinoid Hyperemesis Syndrome: Diagnosis, Pathophysiology, and Treatment: A Systematic Review. J Med Toxicol. 2017;13(1):71 to 87. doi:10.1007/s13181-016-0595-z. PMID: 28000146.

  9. Hsu J, Kashyap S, Hurd C, et al. Treatment of cannabinoid hyperemesis syndrome: A systematic review and treatment algorithm for consultation-liaison psychiatrists. Gen Hosp Psychiatry. 2025;97:185 to 191. doi:10.1016/j.genhosppsych.2025.10.012. PMID: 41129865.

SUPPORT RESOURCES FOR PATIENTS & CAREGIVERS

CHS (Cannabinoid Hyperemesis Syndrome) A Safe Place to Recover and Lean: Peer support for people experiencing CHS and those supporting them.

https://www.facebook.com/share/g/1doNd1MbjA/?mibextid=wwXIfr

CHS Recovery Caretakers: Support for caregivers, family members, and others helping someone through CHS and recovery.

https://www.facebook.com/share/g/19ECMaHKY8/?mibextid=wwXIfr

CHS should be taken seriously without using it to stigmatize medical cannabis patients or people who consume cannabis. Patients deserve to know the warning signs and deserve care that evaluates the whole person, including the medical reasons they were consuming cannabis.

Medical Information Disclaimer

This resource is intended for education and is not a substitute for individualized medical advice, diagnosis, or treatment. Severe or persistent vomiting can have many causes and may require prompt medical evaluation.

Seek medical care for repeated vomiting, inability to keep fluids down, very little urination, marked dizziness, or severe or worsening abdominal pain. Seek emergency help for fainting, confusion, collapse, or blood in vomit.

 

Watch Webinar: Cannabinoid Hyperemesis Syndrome (CHS) Unpacked

 

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