Cannabinoid Hyperemesis Syndrome, known as CHS, is a condition that affects a small number of long-term and heavy cannabis users.
Although recognised in medical literature for nearly two decades, public awareness in the UK remains low.
As a result, many people searching for answers online find only US-based information or conflicting advice.
This UK-focused FAQ covers the most common questions people have about CHS, including what it is, why it happens, how it presents, and what individuals generally do to find relief.
This guide is educational only and not medical advice.
CHS is a condition characterised by episodes of nausea, vomiting, abdominal pain, and a pattern of using hot showers to temporarily ease symptoms.
It typically occurs in people who consume THC-rich cannabis frequently over a long period.
CHS does not appear to be linked to CBD, CBG, or other non-intoxicating cannabinoids.
Current evidence suggests it is specific to repeated high-level THC exposure.
The exact cause of CHS is not yet fully understood, but several mechanisms have been proposed based on clinical research.
Frequent THC use may disrupt normal communication within the endocannabinoid system by overstimulating CB1 receptors in the brain and digestive tract.
THC can reduce nausea in the short term. Over time, however, and especially at high daily doses, this effect may reverse, contributing to nausea instead of relieving it.
Some studies suggest THC may slow gastric emptying, which can contribute to abdominal discomfort and vomiting in susceptible individuals.
Only a small percentage of long-term cannabis users develop CHS. This suggests a genetic or biological predisposition may play a role.
Reports show that CHS typically appears after several years of frequent cannabis use.
Some individuals experience symptoms gradually, beginning with morning nausea or digestive issues before progressing to cycles of vomiting.
People often notice symptoms slowly. Early indicators may include:
This stage is sometimes overlooked because cannabis may temporarily relieve some symptoms before ultimately worsening them over time.
Hot water activates nerve receptors that divert attention away from nausea signals.
The relief is temporary, but it is so common among people experiencing CHS that it is considered a typical behaviour associated with the condition.
During the hyperemetic phase of Cannabinoid Hyperemesis Syndrome, symptoms may include:
Many people seek emergency medical care at this point due to the severity of symptoms.
There is no blood test or scan for CHS. Medical professionals usually diagnose it by:
Most scientific literature reports that the only consistently effective approach is stopping all THC-containing products. Once THC use ends, symptoms generally improve, although recovery time varies.
During an acute episode of Cannabinoid Hyperemesis Syndrome, people commonly seek support from medical professionals. Depending on the severity, this may include:
Some individuals use non-intoxicating cannabinoid products to help them abstain from THC, although results vary and this is not a treatment. This is not medical advice.
Recovery time differs between individuals. Some feel better within days of stopping THC, while others require several weeks. Symptoms typically return if THC use resumes.
People recovering from CHS often focus on:
Some individuals explore CBD products that do not contain THC as part of their transition away from cannabis. This is not a treatment claim.
CHS or Cannabinoid Hyperemesis Syndrome, is not considered permanent.
Most people recover fully once THC use stops. However, symptoms often return if cannabis consumption resumes.
Based on current medical understanding, avoiding chronic high-THC cannabis use is the most reliable way to prevent CHS.
People with a history of Cannabinoid Hyperemesis Syndrome (CHS) should avoid all THC products, as recurrence rates are high.
There is no evidence that CBD, CBG, or other non-intoxicating cannabinoids cause CHS.
These compounds interact with the endocannabinoid system differently, and do not appear to overstimulate CB1 receptors.
You can read our in-depth CHS education guide here which covers Cannabinoid Hyperemesis Syndrome in more detail:
You may also find our article on endocannabinoid system balance helpful:
CBD Before THC Priming Your ECS For Balance
