Patient information factsheet
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Cannabinoid hyperemesis syndrome (CHS)
We have written this factsheet to give you more information about cannabinoid
hyperemesis syndrome (CHS). It explains what cannabinoid hyperemesis syndrome is,
the symptoms to look out for and how it is treated. We hope it will help to answer some
of the questions you may have. If you have any further questions or concerns, please
speak to a member of your healthcare team.
What is cannabinoid hyperemesis syndrome?
Cannabinoid hyperemesis syndrome (CHS) is a rare condition caused by a regular (daily) and
long-term use of marijuana. The syndrome is characterised by repeated and severe bouts of
vomiting.
Marijuana has several active substances. These substances bind to molecules found in the
body and aect the way they work. For example, they aect the molecules found in the brain
and cause the drug ‘high’ that users feel. They also aect the way the molecules in the gut
function and can change the time it takes the stomach to empty. The drug also aects the
oesophageal sphincter, which is the tight band of muscle that opens and closes to let food
pass from the oesophagus (food pipe) into the stomach. The eects of marijuana on your
digestive system are what lead to the main symptoms of CHS.
What causes CHS?
Marijuana is a complex substance that aects everyone dierently. The main ingredient in
marijuana is called THC, which has anti-nausea (anti-sickness) eects. This is why marijuana
is regularly prescribed for nausea caused by chemotherapy treatment. However, if you use
it over a long period of time, marijuana seems to have the opposite eect on the digestive
system and makes you more likely to feel and be sick.
Research is being carried out to explain why only some long-term users of marijuana
experience CHS.
What are the symptoms?
Symptoms are divided into three stages:
Prodromal phase
This is the rst phase and symptoms may include early morning nausea, tummy (abdominal)
pain and a fear of vomiting. During this phase, most people will keep to their normal eating
patterns. Some people may continue to use marijuana because they think it will help stop the
nausea. This phase may last for weeks, months or years.
Hyperemetic phase
Symptoms may include:
• ongoing nausea (feeling sick)
• repeated episodes of vomiting
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• tummy pain
• reduced food intake and weight loss
• dehydration
During this phase, vomiting may often be intense and overwhelming. Many people will take a
lot of hot showers during the day to ease their nausea. The hyperemetic phase will continue
until you stop using marijuana.
Recovery phase
The recovery phase will begin once you stop using marijuana. During this phase, the
symptoms will go away and you will be able to eat normally again. This phase can last days or
months. If you try marijuana again, your symptoms are likely to return.
When should I call my healthcare provider?
Call your healthcare provider if you have had severe vomiting for a day or more.
How is CHS diagnosed?
Many health problems can cause repeated vomiting. To make a diagnosis, your healthcare
provider will ask you about your symptoms and your past health. They will also perform a
physical exam, including an examination of your tummy.
Your healthcare provider may also do further tests to rule out other causes of vomiting.
Admitting to your healthcare provider that you use marijuana daily can speed up the
diagnosis.
How is CHS treated?
If you have had severe vomiting, you may need to stay in hospital for a short time. During the
hyperemetic phase, you may need the following treatments:
• IV (intravenous) uid replacement for dehydration
• anti-sickness medicines
• pain-relief medicines
• proton-pump inhibitors (to treat stomach inammation)
• frequent hot showers
• Capsaicin cream (to reduce pain and nausea)
Symptoms will often ease after a day or two, unless marijuana is used again.
In order to fully recover, you will need to stop using marijuana all together. Some people may
need support from drug rehab programmes to help them quit. Cognitive behavioural therapy
(CBT) or family therapy may also help. If you stop using marijuana, your symptoms should not
come back.
What are the possible complications of CHS?
Very severe, prolonged vomiting may lead to dehydration. It may also lead to electrolyte
problems in your blood. If left untreated, these can cause rare complications, such as:
• muscle spasms or weakness
• seizures
• kidney failure
• heart rhythm abnormalities
• shock
• brain swelling (cerebral oedema)
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What can I do to prevent CHS?
Only stopping marijuana use completely will prevent CHS. Cutting down your use will not get
rid of CHS.
You may not want to believe that marijuana may be the underlying cause of your symptoms.
This might be because you have used it for many years without having any problems, but
CHS can take several years to develop.
Quitting marijuana may lead to other health benets, including:
• better lung function
• improved memory and thinking skills
• better sleep
• reduced risk of depression and anxiety
Where to get help for drugs
Below are some of the services available to help you quit marijuana and other drugs based on
where you live.
FRANK
Telephone: 0300 123 6600
Website: www.talktofrank.com
If you live in Southampton (SO14 to SO19):
Change Grow Live (CGL) (over 25 years old)
Telephone: 023 8071 7171
Email: [email protected]
DASH (under 25 years old)
Telephone: 023 8022 4224
Email: [email protected]
If you live in Hampshire:
Inclusion (over 25 years old)
Telephone: 0300 124 0103
Email: inclusionhants@sss.mhs.uk
Catch 22 (under 25 years old)
Telephone: 0845 459 9405
Email: [email protected]
Information adapted from Cedars-Sinai with kind permission
Version 2. Published April 2023. Due for review April 2026. 2506
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