Cannabinoid Hyperemesis Syndrome, commonly referred to as CHS, is emerging as a serious potential health risk tied to prolonged, frequent cannabis use. Once considered rare, the condition is increasingly recognised by doctors as reports surge of patients arriving in emergency departments with unexplained, recurrent vomiting, nausea and abdominal pain.
CHS typically affects individuals who have used cannabis over many years, often on a weekly or daily basis. In many cases, symptoms only begin after a long period of regular use. The disorder follows a cyclical pattern. In its initial or prodromal stage, sufferers may experience persistent nausea — often worse in the morning — mild abdominal discomfort, loss of appetite or a growing fear of vomiting, even if actual vomiting has not yet started. For weeks or even years many affected individuals may remain in this phase, and some continue using cannabis, mistakenly believing it will relieve the nausea.
As the syndrome progresses into its hyperemetic phase, more severe symptoms emerge. Intense, repeated vomiting — sometimes happening several times per hour — becomes common. This may be accompanied by severe abdominal pain, dry retching, loss of appetite, dehydration and a near-complete inability to tolerate food or drink. Conventional anti-nausea medications frequently fail to provide relief. Some patients experience extreme distress and may seek emergency care.
One strikingly paradoxical feature of CHS is that many sufferers find temporary relief only through hot baths or showers. Although the mechanisms underlying the relief remain unclear, this behaviour — often described as compulsive bathing — has become a recognised hallmark of the syndrome. Medical experts believe that chronic overstimulation from cannabis’s active compounds may disrupt the normal neurochemical pathways governing nausea and vomiting, especially affecting the gut-brain axis.
The only definitive cure for CHS is complete cessation of cannabis use. Once cannabis is stopped, symptoms often ease within days to weeks; in some cases recovery may take months. If cannabis use resumes, the syndrome typically returns.
The health risks associated with CHS extend well beyond the immediate discomfort. Persistent vomiting and dehydration can lead to electrolyte imbalances, malnutrition, kidney damage and other serious complications. In severe cases — especially when dehydration is prolonged or medical care is delayed — outcomes can become life threatening.
Emerging evidence suggests that CHS may be more common than previously thought. As attitudes and laws around cannabis shift, with increased usage especially among younger people, medical professionals are warning of rising rates of what was once considered a rare condition. Many argue that CHS remains underdiagnosed because patients and doctors alike often fail to recognise the connection with long-term cannabis use.
Medical literature describes CHS as a paradoxical reaction: while cannabinoids have well-documented anti-nausea effects, chronic exposure appears to flip that effect in some users, triggering severe vomiting instead. Researchers note that not everyone who uses cannabis develops CHS, and the specific factors that predispose some individuals remain poorly understood. Genetic differences, cannabis potency, frequency of use or other personal health factors may play a role, but no definitive cause has been identified.
The trajectory of CHS is often confusing for patients. Because symptoms may come and go unpredictably, individuals may undergo many rounds of misdiagnosis before receiving the correct explanation. Some are treated for common gastrointestinal disorders — only to see symptoms return again after cannabis use continues. Doctor-patient trust and accurate disclosure of cannabis use are therefore critical for correct diagnosis.
In recent years, health providers have started to raise the alarm about what some call “a silent public health trend.” As medical reporting improves and anecdotal accounts rise — including among adolescents and young adults — the case for greater public awareness of CHS grows stronger. Health education efforts increasingly recommend that frequent cannabis users be informed of this risk.
In sum, Cannabinoid Hyperemesis Syndrome is a serious, sometimes debilitating condition rooted in long-term cannabis consumption. It causes recurring cycles of nausea, vomiting and abdominal pain, often driving affected individuals to seek emergency care. The bizarre paradox of cannabis — a substance known for its anti-nausea properties — causing violent sickness underlines how unpredictable and complex drug effects can be over time. For those affected, full recovery demands complete abstinence; until then, relief remains elusive and unpredictable.