Cannabinoid Hyperemesis Syndrome (CHS) is an under-discussed but increasingly recognised condition that affects a small percentage of long-term, high-frequency cannabis users.
Although it has been documented for nearly two decades, many people in the UK still are not aware that it exists, and many who experience symptoms do not realise cannabis could be the cause.
With medical cannabis prescriptions becoming more common and recreational THC use widespread, CHS is appearing more frequently in clinics and emergency departments across the UK.
Yet many users still doubt whether CHS is real, often because they have used cannabis for years without problems.
This confusion, combined with limited UK-specific information, leaves many people searching online for clear answers.
This guide explains what we currently know about CHS, including symptoms, suspected mechanisms, risk factors, and what people generally do if they believe they might be experiencing it.
This is an educational overview only and not medical advice.
CHS is a condition characterised by cyclical nausea, persistent vomiting, abdominal pain, and a pattern of compulsive hot showers or baths that temporarily relieve symptoms.
It typically affects people who use THC-rich cannabis regularly, often daily or near-daily, over a long period.
CHS was first defined in 2004. Although myths still surround it, there is now widespread clinical evidence that it is a genuine and identifiable syndrome.
Important points:
The condition is not fully understood, but several theories exist.
Heavy and long-term THC use may overload CB1 receptors in the brain and gut, leading to disrupted digestive function.
THC can reduce nausea at low or moderate levels.
At high chronic levels, its relationship appears to reverse, contributing to nausea instead of relieving it.
Some studies suggest THC can slow the movement of food through the stomach, which may contribute to nausea and vomiting.
Research suggests some individuals may be genetically predisposed to CHS, which explains why only a small percentage of cannabis users are affected.
CHS is considered underdiagnosed, so exact UK numbers are not known. However:
The rise in high-strength THC products and daily use patterns likely contributes to this trend.
CHS generally progresses through three stages.
Symptoms usually resolve completely when THC use stops. If THC use restarts, symptoms often return.
Hot showers activate temperature-sensitive receptors in the skin.
This sensory input appears to override or interrupt nausea signals coming from the gut and brain.
The effect is temporary and does not address the underlying cause but is a consistent behavioural pattern in CHS cases.
There is no specific test for CHS. Diagnosis is usually based on:
CHS and CVS share similarities, but key differences include:
Current evidence does not link CHS to CBD, CBG, or other non-intoxicating cannabinoids.
These compounds interact with the endocannabinoid system differently and do not appear to overstimulate CB1 receptors.
For this reason, some people reducing THC intake look toward CBD-based alternatives.
This is not medical advice and not a treatment claim.
The only consistently effective approach documented in medical literature is the complete cessation of THC.
Some individuals may require short-term medical support such as IV fluids during the acute vomiting phase, but symptoms usually recur if THC use resumes.
CHS appears more likely in people who:
CHS is important to understand because:
This guide is for education only. General steps people often take include:
You may also find it helpful to read our article on the relationship between ECS balance and cannabinoid use here: CBD Before THC: Priming Your ECS for Balance.
Many people report that CHS symptoms resolve once THC use stops.
If you want to learn more about cannabinoids or explore compliant CBD options, you may find the following pages helpful. All links open in a new tab.
The following sources were reviewed during the creation of this educational article.
These references are provided for transparency and general information only.
