Days of Vomiting After Daily Use: What a Michigan Hospital Counted on Cannabinoid Hyperemesis

Heads up if you use every day.

If a very hot shower is the only thing that stops days of vomiting, that pattern has a name.

A Kalamazoo, Michigan, teaching hospital counted its emergency visits for cannabinoid hyperemesis syndrome from 2010 through 2025. medRxiv posted that count on October 14, 2026, as a preprint. Peer review means other experts check a paper before a journal prints it, and this one has not had that yet.

The visits are a real chart pull. The count still does not prove legalization caused it, and what drove the jump is an open question.

What did a Kalamazoo hospital count? #

One Kalamazoo teaching hospital recorded 6 of these emergency visits before Michigan adult-use sales. It recorded 274 after, through December 2025, in a medRxiv preprint.

The authors work at Western Michigan University Homer Stryker M.D. School of Medicine. Elizabeth R. Lorbeer led the paper. Joshua D. Mastenbrook, an emergency physician there, is the senior clinical author.

They searched one hospital's electronic charts and kept the visits whose main label was cannabinoid hyperemesis syndrome. Cannabinoid means a cannabis chemical, and THC is the famous one. Hyperemesis means vomiting that will not quit. Syndrome means the signs travel as a pack.

The full window runs January 1, 2010, through December 31, 2025. The authors split it at December 1, 2018, the month adult-use sales began. The earlier slice is 8.9 years and the later slice is 7.1 years.

	Before Dec. 1, 2018	After Dec. 1, 2018	Whole span
Years in the slice	8.9	7.1	16
Emergency visits	6	274	280
Visits per year	0.67	38.59	17.5
Recorded female	5	152	157
Recorded male	1	122	123
Average age	Not listed for this slice	29	29

Those figures are Table 1 of the Kalamazoo preprint. Average age for all 280 visits was 29. Of those 280, 157 were recorded as female and 123 as male.

The authors compared visits per year between the two slices. The later period came out 57.2 times the earlier one, with a 95% range of 26.0 to 157.3. A 95% range is the span the math still treats as plausible. The p value was under 0.0001, which means luck alone rarely makes a gap that big.

That multiple is huge because the early pile is only 6 visits. The authors say a single added or missing case could move it.

The school's review board cleared the project as grouped counts, with no names attached. The board number is WMed-2026-1398.

What the count leaves out #

Those 274 visits are the main-diagnosis list at one Kalamazoo hospital. Detroit emergency departments sit outside this file.

Primary diagnosis means the main reason on the visit. A visit coded as vomiting, dehydration, or belly pain, with cannabis mentioned later, would not land in this pile.

The authors had no month-by-month series, so they cannot tell a slow climb from a cliff. They also cannot tell a true rise in illness from doctors finally using the name. Before legal sales, a lot of these spells may have been filed under a different label.

Kalamazoo is a city of about 73,000 in the Census figures the authors used. Census quickfacts for Kalamazoo is their population source. Henry Ford and the Detroit Medical Center are outside this file. If you live in Detroit, treat 274 as a signal from Kalamazoo.

What is cannabinoid hyperemesis syndrome? #

It is repeated vomiting and belly pain after long, frequent cannabis use. A very hot shower often eases it for a while.

Allen and colleagues in Gut, 2004 wrote the first case series, a write-up of a small group of patients, from South Australia. Chronic cannabis use came before the cyclic vomiting. Stopping cannabis ended the illness in seven cases. Three people who kept using kept getting sick, and three who started again after a break got sick again. Nine of the 10 had a compulsive hot-bathing habit during spells.

A 2011 review by Galli, Sawaya, and Friedenberg splits the course into three phases. There is a lead-up, a hard vomiting spell, and a recovery. The review says the hard spell usually settles within 48 hours, while someone is getting fluids and nausea medicine. Hot bathing can pause the nausea, the vomiting, and the belly pain, but the pause fades. The same review says the cause is still unknown.

Cannabis has a reputation for settling a stomach. This pattern runs the other way. There is still not enough research on why one body flips and another does not.

Rome IV, in Gastroenterology in 2016, is the gut doctors' diagnosis guide. It lists cannabinoid hyperemesis syndrome as its own nausea disorder, next to cyclic vomiting syndrome. Cyclic vomiting means spells that come in repeating cycles, and it can look the same with no cannabis involved.

Blockage, gallbladder trouble, pregnancy, and infection belong in the same first hour at the hospital. A shower clue still needs an exam and a lab.

What are the warning signs? #

Days of vomiting, belly pain, years of frequent use, and relief that shows up in a hot shower. That cluster is the warning.

The largest early chart is the Mayo Clinic series of 98 patients, published in 2012. Every one of those 98 was younger than 50. Belly pain was on file for 84 of them. Hot bathing was written down for 57, and 52 of those 57 (91%) said the hot water helped.

Among 75 with a frequency note, 71 used cannabis more than once a week. Among 37 with a start date, 25 had used for more than two years before the vomiting began.

• Vomiting that comes back in cycles. One bad takeout night is something else. Spells that return are the pattern.
• Belly pain with the vomiting. Present in 86% of the Mayo group.
• A very hot shower or bath as the relief. Nine of 10 in the 2004 series, and most of the Mayo patients who were asked.
• Frequent use for years before the first spell. More than once a week was the common note. More than two years was common when they had a date.
• The spell eases, then returns if cannabis starts again. The 2004 series saw that.

Morning queasiness can be the lead-up phase the 2011 review names, though the review gives no symptom checklist for it. What the case series actually counted was the hard spell plus the shower.

Chest pain or a heart that will not slow down is a separate problem. It has its own page: why cannabis can make your heart race.

Who develops this, and who does not? #

The records point to years of frequent use, often in younger adults. It does not hit most people who use cannabis.

I have used all day for more than ten years. My tolerance isn't a typical tolerance. I write for Divine Toke, a Michigan sun-grown flower project. I have not had this syndrome, and I still want it on the record. People who use the way I use are the group in these charts.

A 2023 case review in Cureus says the syndrome does not occur in most people with long-term use.

The Kalamazoo average age was 29, and the Mayo group was entirely under 50. Seniors are not the main group in these files. Mayo is one health system, though, and someone older than 50 can still show up.

A Detroit auto shift or a hospital night, plus cannabis every evening, fits the frequent-use pattern in the Mayo note. Fitting a pattern leaves the outcome open. You can use every day and never vomit like this. You can also be the person whose mornings turn into a shower that will not let you leave.

The percent on the jar is the wrong place to look for safety. These papers track years of use and how often. The THC number on a label answers a different question. Why a higher THC percent is not automatically stronger is the shopping version of that mistake. Nothing here says a lower percent protects a daily habit.

Did Michigan legalization cause the jump? #

The Kalamazoo count does not prove legalization caused it, and its authors say so. More cannabis use and better recognition are both still on the table.

Michigan voters legalized medical marihuana in 2008. Adult-use sales are the December 1, 2018 line in this paper. The years before that line already included legal medical marihuana. Doctors may also have learned the name later and started typing it. The preprint says both stories fit the same numbers.

A bigger, reviewed study from Ontario makes a cleaner comparison. Myran and colleagues, JAMA Network Open, 2022, tracked cannabis hyperemesis visits for the whole province.

	Ontario emergency visits, Jan. 2014 to June 2021
Visits and people	12,866 visits from 8,140 people
Average age	27.4 years
Share recorded female	51.5%
Visits that led to a hospital bed	1,135 visits, 8.8%
Monthly rate	0.26 per 100,000 people in Jan. 2014, and 3.43 in June 2021
Across the whole span	About a 13-fold rise
At legalization, with tight store rules	No immediate jump, and no slow step-up
When stores and products expanded, during COVID	Rate about 49% higher right away (1.49 times the old rate, 95% range 1.31 to 1.70)

Legalization in that paper means October 2018 through February 2020, with product and store limits. The later window, March 2020 through June 2021, is more stores and a wider menu. It also sits on top of the COVID-19 pandemic, and the authors cannot pull the stores apart from the pandemic.

Ontario does not show a switch flipping on opening day. The visits climbed hard across 7.5 years, and the statistical step showed up when the market got big during the pandemic.

Kalamazoo is a smaller tool. It covers one hospital and main diagnosis only. The authors compared two block totals, because a month-by-month line was unavailable. With six early visits, the 57.2 multiple is real math on a shaky base.

Side by side, the two papers say emergency visits with this label rose in places with legal sales. Neither gives a Michigan statewide rate. Neither lets you blame one law and stop there.

Hospital bills rose at one Massachusetts hospital too. Marshall and colleagues, Journal of Clinical Gastroenterology, 2024, looked at 72 hospital stays they treated as this syndrome, from 2012 to 2021. Mean cost was $7,460 before that state's legalization date and $18,714 after. Adjusted for inflation, the early figure is $8,520 against the same $18,714. Length of stay went from 1 day to 3 days.

Those dollars belong to one urban hospital in Massachusetts. They show how long these stays can run once someone is admitted.

What do emergency rooms use for the vomiting? #

Fluids first. In a small trial, haloperidol beat a standard nausea drug for the spell. Chili-pepper cream has mixed results.

Galli's 2011 review says care for the hard spell is fluids and nausea medicine. The spell often settles inside 48 hours with that support. Haloperidol is an older drug emergency rooms use for hard nausea and for severe agitation. Ondansetron is a nausea drug many ERs reach for first.

The HaVOC trial in Annals of Emergency Medicine randomly assigned people who were actively vomiting and using cannabis. Thirty people got at least one of the drugs. Thirteen got haloperidol, and seventeen got ondansetron.

At two hours, haloperidol did better on belly pain and nausea. The gap was 2.3 centimeters on a 10-centimeter scale, with a 95% range of 0.6 to 4.0. Time until leaving the ER averaged 3.1 hours with haloperidol and 5.6 hours with ondansetron. Two people came back with a sudden muscle spasm, and both were in the group that received more haloperidol. Thirty people is a small trial, and haloperidol is a hospital drug.

Capsaicin is the burn in a chili pepper. Some ERs have used it as a cream on the skin of the belly. The 2024 SAEM GRACE review in Academic Emergency Medicine pulled seven studies and 492 people. Five studies, with 386 people, looked at capsaicin cream. The evidence on nausea and vomiting was mixed.

Two studies, with 106 people, looked at dopamine blockers, including haloperidol and droperidol. Dopamine is a brain chemical those drugs turn down. Both studies saw a benefit against usual care. The reviewers still call the whole evidence pile thin.

If you cannot keep water down, the ER is the room with the IV. Any cream belongs in a monitored visit.

Can days of vomiting injure your kidneys? #

Yes. A day or two of vomiting can dry you out, and that water loss can injure the kidneys.

The 2023 Cureus review says severe nausea and vomiting can last 24 to 48 hours. That spell may bring dehydration, acute kidney injury, and salts in the blood going off. Dehydration means the body is short on water. Acute kidney injury means the kidneys are struggling right now, often because that water is gone.

The review's own case is one man whose kidney numbers had been normal four months earlier. On arrival they were not. They recovered over two days after fluids and a stop in the vomiting. One case cannot give a rate, but it shows the risk the review is warning about.

Barely peeing, confusion, fainting, or vomiting that will not let you drink are ER problems the same day. Kidneys need fluid from an IV, or from drinks you can keep down.

What warning does a Michigan shop have to give you? #

State law tells the agency to require a small pamphlet at sale. The named topics are use by minors and the poison hotline. This syndrome is not on the list.

Adult-use rules sit in MCL 333.27958, which tells the cannabis agency to set pamphlet standards for marihuana retailers and microbusinesses. The pamphlet in the statute is 3.5 inches by 5 inches. Every customer is supposed to be able to get one at the time of sale.

The required topics named there are safety information on marihuana use by minors, and the poison control hotline number. The national Poison Help line is 1-800-222-1222. HRSA's Poison Help page is the public home for that number.

The same section requires a boxed pregnancy warning on the package. The warning covers pregnancy, breastfeeding, preterm birth, low birth weight, and developmental problems. Vomiting is missing from that boxed warning.

Medical provisioning centers follow MCL 333.27206, with the same size pamphlet and the same two named topics. A licensed adult-use counter in Detroit is a retailer under the adult-use section. The pamphlet standard applies at adult-use counters across the state.

The Kalamazoo team also looked at what shops and health departments actually publish online. They used the Michigan Cannabis Regulatory Agency licensee list on July 15, 2026, and found 34 retailer licenses in Kalamazoo zip codes. Nineteen were active and got reviewed. One of the 19 mentioned cannabinoid hyperemesis, buried in an education booklet. That mention did not list symptoms or say when to get care.

In July 2026 they also searched the Michigan Department of Health and Human Services site and the Kalamazoo County health site. They did not find cannabinoid hyperemesis on either one. Printed pamphlets at the counter were mostly not posted online, and the authors say they could not confirm every paper handout. The one booklet they did find named the syndrome and then stopped.

Their ask is to add a real warning to the pamphlet the state already requires. That ask is a recommendation in a preprint, and it is still only in the preprint.

What should you do if this is your morning? #

Go in if you cannot keep water down. Tell them you use cannabis. The step that lasts, in the case reports, is stopping.

The 2004 Gut series and the 2012 Mayo series are the reason clinicians call stopping the only reliable cure. In the first series, quitting lined up with the illness ending, and starting again lined up with the illness coming back.

The 2012 Mayo series could follow only 10 people. Seven of those 10 stopped, and six of those seven had complete relief. The follow-up is small, but it is still the only step in those files that held. Fluids and haloperidol are for the spell in the room. They do not replace a stop if the cannabis continues.

1. Get to an ER if drinks will not stay down. A friend should drive. Barely peeing, fainting, confusion, vomit with blood, or chest pain means the same day, and chest pain can be a 911 call.
2. Say that you use cannabis. Years of use, how often, and the hot shower belong in your first sentence. How to tell a doctor you use cannabis is the script for the calmer visit after.
3. Let them check fluids and kidneys if the vomiting has run a day or more. That check covers the dehydration risk above.
4. Treat the shower as a clue. It tells the story of the spell, and an IV replaces the water you lost.
5. Plan a real stop for more than a night. The science of a tolerance break covers what the first days feel like. In the 2004 series, going back brought the vomiting back.
6. If you are in cancer treatment, call that team before you change anything. Cannabis for chemo nausea is a different problem, covered in the chemo nausea guide. Do not drop a cancer plan because of a Kalamazoo chart.

Ordinary gut trouble, the kind people shop terpenes for, is a different page: cannabis and gut comfort.

Frequently asked questions #

The Kalamazoo count is a preprint. Stopping is the step the case reports tie to a lasting end.

What is cannabinoid hyperemesis syndrome? #

It is days of vomiting and belly pain after long, frequent cannabis use, often eased only by a very hot shower.

Allen's 2004 series tied the illness to chronic cannabis use and to compulsive hot bathing in 9 of 10 cases. Rome IV, the gut doctors' guide, lists it as its own nausea disorder.

A shower is a clue you can tell the doctor. The diagnosis still happens at the hospital.

Is the Kalamazoo paper peer reviewed? #

No. It is a preprint posted on medRxiv on October 14, 2026, and a journal has not reviewed it yet.

medRxiv's banner says a preprint should not guide clinical practice. The visit counts come from one hospital's charts, so read them as a tally. They do not prove legalization caused the rise.

The practical steps on this page come from the older reviewed papers. The preprint's pamphlet idea is a recommendation.

How many emergency visits did that Kalamazoo hospital count? #

Six before December 1, 2018, and 274 from that date through December 2025. The total is 280.

The preprint puts the later rate at 57.2 times the earlier one. The range is 26.0 to 157.3, because the early count is only 6. Average age was 29. The file is one Kalamazoo teaching hospital.

Does a hot shower prove this is the cause? #

No. It is the clue that showed up in the case series, and plenty of other illnesses make people want heat.

In the Mayo series, 52 of 57 people asked about hot water said it helped. An ER still has to check for blockage, pregnancy, infection, and other causes.

Tell them about the shower. Do not skip the visit.

How long do people usually use cannabis before this starts? #

In the Mayo file, more than two years was common, and more than once a week was the usual frequency. The first night is the wrong timeline.

The 2012 Mayo paper had a duration note for 37 people. Twenty-five of them had used for more than two years before symptoms. Of 75 with a frequency note, 71 used more than once a week.

The Kalamazoo average age of 29 fits a young-adult chart. A single first night does not match these files.

Does stopping cannabis end it? #

In the case reports, stopping is the only reliable cure for the cycle. The groups they could follow are small.

Allen, 2004: seven people who stopped got well, three who continued stayed ill, and three who restarted got sick again.

Mayo, 2012: of 10 patients with follow-up, 6 of the 7 who stopped had complete relief.

ER drugs can quiet one spell. In the files, the cycle came back when cannabis came back.

What do emergency rooms use for the vomiting? #

Fluids, and sometimes haloperidol. Capsaicin cream, from chili pepper, has mixed evidence.

The HaVOC trial found haloperidol better than ondansetron at two hours in 30 people. Two of them came back with a muscle spasm, both from the group that received more haloperidol. The 2024 GRACE review calls the capsaicin evidence mixed and the dopamine-blocker evidence limited but favorable.

Neither paper is a reason to skip the ER and treat this on a couch.

Can the vomiting hurt your kidneys? #

Yes. A day or two without fluids can injure the kidneys.

The Cureus review ties 24 to 48 hours of vomiting to dehydration and acute kidney injury. If you are barely peeing, or you cannot keep water down, that is an ER visit today.

If I use cannabis for nausea, should I throw the jar out? #

No. Help with nausea and this syndrome are different patterns, and most long-term users never get the syndrome.

The chemo nausea guide covers the nausea side. The Cureus review says this does not happen to most people who use long term. If you are in cancer care, talk to that team before you change a plan.

If your relief is a scalding shower after days of vomiting, this article is about you.

Does a higher THC percent raise the risk? #

These studies describe years of frequent use. A percent on a label sits outside them.

The THC percent myth is about how a high feels, and it is the wrong shield here too. A lower number on a jar does not erase a daily habit that has run for years.

Should I tell my doctor? #

Yes. The hot shower, the years of use, and the vomiting belong in the first minute.

Hiding cannabis use sends the workup toward every other cause of vomiting. Those still need checking, and the right label comes later. The visit script is the plain version for that appointment.

The Kalamazoo preprint argues people often learn the name in an ER, because the counter pamphlet never mentions it.

Is this the same as a stomach bug? #

A stomach bug ends. This pattern cycles, tracks with long cannabis use, and often eases in a hot shower.

Food poisoning and a virus can still be the real answer on any given day. Blood in the vomit, severe one-sided belly pain, or a positive pregnancy test still need a doctor the same day. If the shower is the only relief and the use has been frequent for years, say that out loud at the ER.

If this sounds like you #

You can take this seriously and still go in for help.

I use every day, and my tolerance isn't a typical tolerance. I have not had this syndrome. I still want it in daylight for people who use like I do.

The Kalamazoo count is one hospital and a preprint. The shower clue, the years of use, the kidney risk, and the stop come from older papers. If drinks will not stay down, go in and tell them the truth. A doctor who hears the whole story can help faster.

When you are well, give the cannabis a real stop. The tolerance-break science is the map for the first hard days.

This article is for educational purposes only and is not medical advice. Always consult your healthcare provider before starting any new wellness routine.