Regular cannabis use can cause a serious vomiting syndrome. Should people be warned?

Shaki Sutharsan · CBC News

· Posted: Jul 03, 2025 4:00 AM EDT | Last Updated: 10 minutes ago

When Brittany Ramsey started experiencing "awful tummy episodes" she thought it must've been broadside effects of the medicine she was taking to negociate her diabetes.

But aft a peculiarly gruelling occurrence wherever she conscionable could not halt vomiting — not being support down even small sips of h2o — that landed her successful hospital, Ramsey knew thing felt antithetic astir what she was experiencing.

"From then, the episodes got worse and worse, and person together," said Ramsey, a 35-year-old operations trainer astatine a fiscal steadfast successful Cincinnati, Ohio. "From 2021 to 2024 … 3 years, I was hospitalized 29 times. Five ambulance trips – 1 really had to prime maine up connected the broadside of the roadworthy due to the fact that I couldn't marque it to the hospital."

After years of undergoing, astatine times, invasive investigating procedures to regularisation retired Crohn's disease, gastroparesis and diverticulitis, a doc told Ramsey astir cannabis hyperemesis syndrome (CHS). 

In caller years immoderate exigency rooms person been seeing an uptick successful visits owed to cyclic episodes of uncontrollable vomiting successful cannabis users, often characterized by experiencing impermanent alleviation with blistery showers and baths. Since it was archetypal identified successful aesculapian lit successful 2004, CHS cases person increased, perchance due to the fact that of greater cannabis entree or higher THC potency of products.

Public wellness researchers suggest much consciousness of CHS wrong the health-care strategy is needed for cannabis users to get the accusation and enactment they need.

More CHS cases successful the ER

CHS is characterized by "severe and persistent vomiting" and is usually seen successful radical who person been utilizing cannabis respective times a week for aggregate years, said Jamie Seabrook, a prof astatine the Department of Epidemiology and Biostatistics astatine Western University successful London, Ont.

Ramsey said she'd been smoking astatine slightest erstwhile a time for implicit 10 years since she was 18 erstwhile she archetypal started experiencing CHS symptoms successful 2017.

A 2022 survey by researchers astatine the Ottawa Hospital Research Institute looked astatine the complaint of exigency section visits for CHS aft recreational cannabis was legalized and commercialized successful Ontario, looking astatine astir 13,000 CHS-related hospitalizations successful Ontario from 8,140 individuals betwixt 2014 and 2021. 

The study, published successful the Journal of the American Medical relation (JAMA), recovered that exigency section visits related to CHS had accrued by 13-fold implicit a play of astir 8 years. The survey doesn't amusement what caused the change, but the authors noted that the biggest summation successful visits came not aft legalization successful 2018 but aft Ontario allowed enlargement of retail stores successful 2020, which coincided with the COVID-19 pandemic. 

Though we don't person numbers however galore radical person been diagnosed oregon hospitalized with CHS, online communities are filled with radical looking for support. 

Ramsey is portion of 1 of them — a CHS Facebook radical described arsenic a "safe spot to retrieve and learn" with 3,000 members. The largest CHS Facebook radical has 31,000 members. On Reddit, the radical r/CHSinfo has 20,000 members, with discussions ranging from tips connected however to negociate episodes and idiosyncratic anecdotes astir repeated hospitalizations. 

Seabrook, who co-authored a caller reappraisal of existing probe connected CHS successful youth, said there's been an "explosion" of radical showing up successful immoderate North American exigency rooms with CHS wrong the past 7 to 8 years.

The Ottawa Hospital Research Institute survey showed that different cannabis-related exigency country visits, including for intoxication and dependence, saw a important summation starting successful aboriginal 2020 arsenic well. 

Surge successful THC potency since the 1980s 

Seabrook said a apt crushed for accrued rates of CHS is the precocious THC potency of cannabis products today.

THC is the compound successful cannabis that is liable for the sensation of a precocious astir radical acquisition erstwhile consuming it. When its potency increases, truthful bash its harmful effects. 

Different strains of the works volition person antithetic concentrations of progressive compounds, measured by percent of full value oregon volume. On average, THC contented is overmuch higher contiguous than it utilized to be.

"The potency of THC was lone astir 3 per cent in the 1980s and today, according to Health Canada, the mean is 15 per cent with immoderate strains arsenic precocious arsenic 30 per cent," Seabrook said, citing Health Canada numbers for "fresh oregon dried herb material." 

"So we're talking a 400 per cent or higher summation successful the potency." 

For "chemically concentrated extracts," specified arsenic hash oil, shatter, budder and wax, the emblematic potency tin beryllium up to 90 per cent, according to Health Canada data.

"The potency, I think, is what's causing the illnesses to go much and much prevalent, due to the fact that they're smoking a batch much potent stuff," Ramsey said. "And that's the aforesaid with me. When I archetypal started smoking, it was my brother's homegrown stuff, versus getting it from friends and dispensaries retired successful California, wherever it does get stronger and stronger."

"I consciousness similar possibly earlier conscionable making marijuana disposable to the masses, possibly immoderate of these things should person been looked into. You know, excessively overmuch of thing mightiness beryllium bad," said Ramsey.

Lawsuit against Aurora Cannabis cites CHS 

A suit was precocious brought against Canadian cannabis accumulation institution Aurora Cannabis for alleged negligence of failing to pass consumers about the imaginable hazard for processing CHS from the regular usage of its products. The suit was certified by the Ontario Superior Court of Justice past month, meaning it tin proceed arsenic a people action. 

Margaret Waddell, the lawyer prosecuting the case, said she hopes that if the suit is successful, it could person an industry-wide effect connected including CHS successful their merchandise labelling. 

"Ideally, Health Canada volition necessitate them astatine immoderate point," Waddell said. Health Canada does necessitate cannabis manufacturers to pass customers astir specified risks — including psychotic symptoms, addiction and dependence — but Waddell said determination aren't presently immoderate requirements to specifically see CHS successful those warnings. 

Aurora Cannabis declined to remark connected the lawsuit, penning successful an emailed statement: "It is the company's signifier not to remark connected ineligible matters beyond accusation that is made disposable to the public."

"Information that [CHS] exists is precise important," Seabrook said. "In schools, successful health-care settings – whether that's neurologists, psychiatrists, [emergency room] doctors – and nationalist wellness campaigns, truthful radical tin marque a amended informed determination astir their cannabis use."