What on earth is Cannabinoid Hyperemesis Syndrome?

We take a look at the research to see if people who vape CBD have any cause for concern.

Cannabinoid Hyperemesis Syndrome (CHS), is an extremely rare condition that has been only been diagnosed in heavy, long-term cannabis users. Often mistakenly diagnosed as Cyclical Vomiting Syndrome (CVS), CHS is described as an uncommon form of cannabinoid toxicity that can develop from chronic usage.

Since so few people have ever been diagnosed with the condition, and since the availability of CBD oil for vaping is relatively new, there is no current evidence to suggest that any CBD vapers have developed CHS.

So then, why are we writing about it?

Good question! We’ve noticed that people have been searching our website for instances of the terms CHS and CVS. Presumably, being conscientious consumers, they want to check if there are any known risks associated with vaping CBD. As responsible CBD vaping suppliers, we wanted to ensure that we provide the answer to that concern.

What is CHS?

Cannabinoid Hyperemesis Syndrome is characterised by recurrent nausea, vomiting and abdominal cramps. It’s really important to remember that loads of other conditions can also be characterised by these symptoms, including CVS which CHS is often mistaken for.

The term CHS was first used after a 2004 study in Australia where scientists explored the possible association between chronic cannabis use, and a cyclical vomiting illness that presented in ten cases.

All of the patients involved in the study had been smoking cannabis for many years (no concentrates, edibles, or vapes). Seven out of the ten abstained from smoking marijuana and their symptoms completely resolved. The three patients that chose not to abstain saw their symptoms persist.

Interestingly, what they discovered was that nine out of ten of the patients reported a compulsion to take hot showers or baths during symptomatic episodes. This characteristic has been pinpointed by other clinical studies since, making it a major criteria in the diagnosis of CHS.

How is CHS diagnosed?

In order to be confident of a correct CHS diagnosis, healthcare professionals work to the following clinical criteria.

Essential criteria

Ongoing, long-term, regular cannabis usage

Major criteria

Severe cyclic nausea and vomiting

Resolved by cannabis cessation

Symptoms relieved by taking a hot shower or bath

Abdominal pain

Supporting criteria

Patient is less than 50 years old

Weight loss greater than 5kg

Predominance of symptoms in the morning

Normal bowel movements

Cannabis use started during teenage years

What is the difference between CHS and CVS?

Ultimately, a complete history of the patient’s use of cannabinoids is the essential factor in establishing the correct diagnosis. However, there are a few other clinical criteria that healthcare professionals would take into account.


Criteria CHS CVS
A trigger such as infection or stress Absent  Frequent
Sex Mainly males  Mainly females
Frequent and compulsive hot showers or baths Universal  Absent
Psychiatric disorders Rare  Frequent
Migraine Rare Frequent
Urine cannabinoid screen Typically positive Typically negative


Why is CHS suddenly in the news?

The diagnosis of CHS involves disclosing heavy, long-term cannabis usage to healthcare professionals. Since marijuana has only recently been widely de-criminalised, it’s possible that some cases of CHS have been reported as CVS. Recent changes to the legality of cannabis could mean that people feel more comfortable admitting to their habit.

As reported instances increase, further clinical studies are commissioned across the globe to get to the bottom of the causes of CHS. The reports also lead to the media picking up and running with the stories, presumably with the aim of scaremongering. The media has also coined some new terms for CHS which have been hitting the news - for example, one California publication ran with ‘Stoner-Barf’ (yes really!).


Why could cannabis cause CHS?

It’s kind of paradoxical that cannabis could be associated with vomiting, since one of the key benefits of cannabis is its antiemetic quality.

As mentioned previously, there have been several clinical studies, and many other theories.

One study from Temple University in Pennsylvania theorises that the activation of CB1 receptors could lead to gastrointestinal reactions.

Others believe that genetics can lead to cannabinoids reaching toxic levels in sensitive patients.

Some think that cannabis may cause a disequilibrium in the body’s temperature regulation system of certain people. This theory is borne out further when considering the hot bathing compulsion.

Then there are those who suspect that potent strains of marijuana, or even the chemicals used for enhanced growth may have lead to the more recent uptick in reported cases.

All of these are just theories at this point. There are still many skeptics out there who don’t believe that CHS is related to cannabis use at all. A 2006 Australian clinical study criticised the previous 2004 study claiming ‘poor design and inaccurate results’.

“Cannabis has been consumed for many centuries and is currently used by millions of people in many countries. It is hard to believe that a distinctive syndrome caused by cannabis has never been noted before by users or clinicians.”

I vape CBD oil everyday - will I get CHS?

If we go by the number of reported cases of CHS vs. worldwide cannabis usage the answer would be - probably not!

It’s safe to say that CHS is very rare. The array of scaremongering headlines are exaggerating the problem somewhat.

Even if there does turn out to be a conclusive link between CHS and cannabis use, it’s important to remember that instances are uncommon. If you are finding a benefit from using CBD oil, these stories shouldn’t deter you.

Forewarned is forearmed, so it is important for you to be aware of the syndrome’s existence. If you do develop any of the symptoms associated with CHS, stop vaping CBD, talk to your doctor or healthcare professional, and disclose your CBD history.


If you need any more help or advice in relation to vaping CBD, talk to us. We’re always on hand to answer your questions.