Cannabinoid Hyperemesis Syndrome (CHS): How Long Recovery Takes, Symptoms, and Treatment

What cannabinoid hyperemesis syndrome is

Cannabinoid hyperemesis syndrome, or CHS, is a pattern of repeated episodes of intense nausea, vomiting and belly pain in people who use cannabis often and for a long time. Between episodes a person may feel fairly normal. The cause is not fully understood, which is part of why it is so often missed: cannabis is better known for easing nausea than for causing it.

The American Gastroenterological Association’s 2024 clinical practice update lists three criteria doctors use: episodes of vomiting that follow the same pattern, three or more times a year; cannabis use for more than a year before symptoms began, on average more than four times a week; and symptoms that go away once cannabis has been stopped for at least six months, or for at least as long as three of that person’s usual vomiting cycles.

A 2017 systematic review in the Journal of Medical Toxicology pooled 183 reports. Every case involved regular cannabis use and cyclic nausea and vomiting. Symptoms resolved after stopping cannabis in 96.8 percent, 92.3 percent reported compulsive hot bathing that relieved symptoms, 85.1 percent had belly pain, and 72.9 percent were men.

The three phases and how long each lasts

Clinicians usually describe CHS in three phases, as a 2011 review lays out.

How long does it take to recover from CHS?

There are two answers, and they get mixed up. A single bad episode usually settles within a day or two, especially with fluids and the right medicine. Recovery from the syndrome is slower and depends on one thing: staying off cannabis. That is why the AGA’s diagnostic rule asks for at least six months of abstinence, or the length of three typical cycles, before saying symptoms have truly resolved. Someone who feels fine a week after an ER visit and starts using again can expect the episodes to come back.

Stopping daily cannabis can bring its own short-term withdrawal: irritability, trouble sleeping, lower appetite, anxiety, and in some people nausea and stomach pain, which can be confused with CHS. A 2017 review of cannabis withdrawal describes it as mostly mood and behavioral symptoms of light to moderate intensity, usually manageable as an outpatient, and notes the brain’s cannabinoid receptors return to normal function within about four weeks of stopping.

Why hot showers help, and why they are not a treatment

Long, very hot showers or baths are so common in CHS that the 2017 review counted them in more than nine in ten reports, and the 2011 review calls it a learned behavior: people discover the heat brings temporary relief and repeat it, sometimes for hours. The relief is real but brief, and it does nothing to stop the next episode. Very hot water can scald, and hours in a hot shower while vomiting adds to dehydration.

What the emergency room can do

Ordinary anti-nausea medicine is not always enough in CHS. The 2017 review found some benefit from IV fluids, dopamine-blocking medicines, and capsaicin cream (the compound that makes chili peppers hot) rubbed on the belly, and advised avoiding opioid pain medicines.

The best direct comparison is a 2021 randomized trial in Annals of Emergency Medicine of 30 patients. IV haloperidol relieved pain and nausea more than ondansetron (Zofran), and patients given haloperidol needed fewer rescue medicines and left the ER sooner, about 3 hours versus 5.6. Two patients in the higher-dose haloperidol group came back with acute dystonia, a muscle-spasm reaction to the drug. That is a decision for the ER team, not a home remedy.

Can CHS kill you?

Rarely, but it can. A 2019 report in the Journal of Forensic Sciences described three deaths in people in their late twenties and early thirties with a history of CHS, all seen in an emergency department for vomiting in the days before they died; the cause of death was attributed to CHS in two. The danger is the vomiting itself: water and salt losses that can injure the kidneys and disturb heart rhythm. That is why not keeping fluids down is a reason to go in, not to wait it out.

CHS is not the same as greening out

Greening out is taking more cannabis than the body can handle at one time and feeling sick, shaky or panicked for a few hours; it can happen to a first-time user. CHS builds over months or years of frequent use and comes back in cycles. Our greening out guide covers the one-time version.

Stopping cannabis in New Jersey

For most people, stopping cannabis does not need a detox bed; the 2017 withdrawal review describes outpatient care as usually enough. A higher level of care makes sense when cannabis is combined with alcohol, benzodiazepines or opioids, or when depression, anxiety or another health problem is in the way. Our guide to the signs someone needs detox helps sort that out, and the outpatient treatment guide explains what counseling-based care looks like.

In New Jersey

Fully insured New Jersey plans and the State Health Benefits and School Employees’ plans cannot require prior authorization for the first 180 days per plan year of in-network treatment your own physician, psychologist or psychiatrist finds medically necessary. Self-funded employer plans, Medicare and Medicaid are not covered by that rule. NJ FamilyCare (Medicaid) members and people without insurance can call the IME Addictions Access Center at 1-844-276-2777, which screens callers and refers them to treatment. ReachNJ, at 1-844-732-2465, is the state’s treatment referral line. Both answer 24/7. Same-day admission is sometimes possible; it is not guaranteed. For what a specific plan covers, see the insurance guides.

Periscope Behavioral Health, which publishes this site, is opening a medical detox in Hammonton, Atlantic County, expected Summer 2027. Until then, the admissions line of our publisher, Periscope Behavioral Health, at (888) 313-3583, can talk through options in New Jersey and Florida, including facilities Periscope operates. What a plan covers depends on the plan and the facility’s network status.