As cannabis becomes more widely accepted and legalized, a little-known but increasingly common condition is catching many families and healthcare providers off guard: Cannabinoid Hyperemesis Syndrome (CHS). In our recent publication, our research team explores this troubling syndrome, which is characterized by severe, repeated vomiting triggered by long-term and frequent cannabis use.

Though still unfamiliar to many, CHS is on the rise, particularly among youth. In fact, emergency department visits for the condition in the U.S. and Canada have doubled between 2017 and 2021. This trend reflects both the increased availability of high-potency cannabis products and the growing normalization of regular use. In fact, 18% of U.S. 12th graders reported using cannabis in the past month.

CHS does not start dramatically. In the early “prodromal” phase, young people may wake up feeling nauseated and mistakenly believe that using more cannabis helps. Over time, however, they can progress to the hyperemetic phase. This stage is marked by uncontrollable vomiting, abdominal pain, dehydration, and weight loss due to the inability to retain food or fluids. Many affected youth find only temporary relief through long, hot showers or baths, a curious but now well-documented hallmark of CHS. Recovery typically begins only after cannabis use is completely stopped. However, that is often a difficult step for those already using the drug to cope with stress or anxiety.

This issue is worsened by the fact that cannabis today is not what it used to be. THC concentrations, the main psychoactive compound in cannabis, have quadrupled in recent decades, making negative side effects more likely. High-potency cannabis use among youth has been linked to increased risk of depression, anxiety, paranoia, psychosis, and even self-harm. While occasional use doesn’t typically cause CHS, daily or weekly use over an extended period, especially with high-THC products, can be enough to trigger the syndrome.

Contrary to widespread belief, cannabis is not always calming. In some individuals, especially youth, THC can disrupt the body’s natural stress response and gastrointestinal system. Because the brain continues to develop until around age 25, frequent high potency THC exposure during this critical period can interfere with neural growth and the formation of brain circuits responsible for attention, memory, and learning.

One of the biggest challenges with CHS is that it is often misdiagnosed or overlooked entirely. Many physicians are unfamiliar with it, and youth may not disclose cannabis use due to stigma or fear of judgement. This can lead to unnecessary ER visits, expensive imaging tests like MRIs and CT scans, and incorrect diagnoses such as eating disorders like bulimia. But CHS-related vomiting is involuntary, driven by physical factors and not body image concerns.

Treatment is not straightforward either. Standard anti-nausea medications are often ineffective. Some emergency rooms have found success using topical capsaicin cream or medications like haloperidol, which target different pathways involved in CHS. However, the only reliable long-term solution is quitting cannabis use. That is often easier said than done, particularly for youth who may be using it to cope with underlying emotional challenges. For individuals who persist with cannabis use despite clear information linking it to their CHS symptoms, it may be appropriate to involve addiction specialists, substance use counselors, or rehabilitation services. This continued use could also indicate that cannabis has a higher potential for dependence than commonly believed.

So, what can we do? Addressing CHS requires a coordinated response that spans prevention, clinical care, research, public health, and policy. The first step is education. Prevention efforts should begin early, with school-based awareness programs, public health campaigns, and healthcare messaging that clearly communicate the risks of frequent cannabis use, including CHS. Parents, educators, and counselors should also be involved in recognizing early symptoms, such as morning nausea or reliance on hot showers to ease discomfort.

Public health messaging also needs to keep pace with the changing cannabis landscape. As legalization increases access and normalizes use, information about the potential harms of chronic cannabis consumption must be more visible. CHS should be included in these messages to ensure both users and healthcare providers are informed.

Early recognition by clinicians is essential. When youth present with repeated vomiting, abdominal pain, or unexplained gastrointestinal symptoms, CHS should be considered. Screening questions about cannabis use and symptom relief from hot water can be useful diagnostic tools.

There is also a clear need for more research. Studies are needed to better understand the causes of CHS, its risk factors, and the most effective treatments. Randomized controlled trials and population-based research will help inform evidence-based care.

CHS may still be underrecognized, but with coordinated action, its impact on youth health can be significantly reduced.

Dr. Jamie Seabrook is a Professor in the Department of Epidemiology and Biostatistics at Western University, with cross-appointments in the Department of Paediatrics, as well as the Brescia School of Food and Nutritional Sciences. Dr. Seabrook is also a Scientist with the Children’s Health Research Institute, Lawson Research Institute, and London Health Sciences Centre Research Institute in London, Ontario, and a Faculty Associate of the Human Environments Analysis Laboratory. Dr. Seabrook’s research focuses on the social determinants of child health disparities and youth substance use. In 2019, Dr. Seabrook received the Award for Excellence in Research at Brescia University College affiliated with Western University. You can follow them on X: @Jamie_Seabrook1