Cannabinoid hyperemesis syndrome (CHS) feels like relentless, uncontrollable vomiting paired with waves of nausea and a dull ache in your upper abdomen. It typically hits people who use cannabis daily or near-daily, often after a year or more of regular use, though it can develop in as little as a few months. The experience unfolds in distinct phases, each with its own set of sensations.
The Early Warning Phase
CHS doesn’t start with dramatic vomiting. It begins with a prodromal phase that can last weeks or even months, and it’s easy to dismiss. The hallmark feeling is morning nausea, the kind that greets you when you wake up and sits in your stomach without actually making you throw up. You might also notice vague abdominal discomfort that’s hard to pin down. Many people chalk this up to stress, a bad diet, or even a hangover and keep using cannabis, sometimes specifically to treat the nausea, which only deepens the cycle.
What a Full Episode Feels Like
The hyperemetic phase is when CHS becomes impossible to ignore. The nausea escalates into violent, repeated vomiting that doesn’t respond to the usual remedies. People describe it as relentless: you may vomit multiple times per hour, sometimes reaching 12 to 15 episodes in a single day. The vomiting feels forceful and involuntary, often producing mostly bile or dry heaves once your stomach is empty.
The abdominal pain during these episodes typically settles in the upper stomach area (epigastric region) and feels diffuse rather than sharp. It’s a deep, achy discomfort that intensifies with each round of vomiting. Your body may also show signs of nervous system overload: rapid heartbeat, sweating, tremors, hot flashes, and spikes in blood pressure. These symptoms make the whole experience feel like a full-body crisis, not just a stomach problem.
One of the strangest and most distinctive sensations is an overwhelming, almost compulsive urge to take a hot shower or bath. People with CHS often describe feeling like scalding water is the only thing that provides any relief at all. It’s not just preference. It’s a learned, driven behavior where you may spend hours in the shower because stepping out immediately brings the nausea flooding back. This happens because heat activates the same pain and temperature receptors in your body that the endocannabinoid system interacts with, temporarily overriding the nausea signal.
How It Differs From Food Poisoning or a Stomach Bug
CHS episodes feel different from ordinary vomiting in several ways. Food poisoning or a virus typically peaks within hours and then gradually fades. CHS episodes can cycle for 24 to 48 hours or longer, and they repeat in patterns over weeks or months. Standard anti-nausea medications that work for other conditions often do nothing for CHS, which is part of what makes it so frustrating. The hot shower relief is another major clue. If you find yourself unable to leave the shower because it’s the only thing stopping the vomiting, that pattern is strongly suggestive of CHS.
CHS also closely resembles cyclic vomiting syndrome (CVS), and the two can be nearly impossible to tell apart based on symptoms alone. The most reliable way to distinguish them is that CHS resolves completely when cannabis use stops. People with CVS are more likely to have a history of migraines and mental health conditions like panic disorder or depression, but these overlap enough that they aren’t definitive on their own.
Who Gets CHS and How Quickly
In a case series of 98 patients, 59% used cannabis daily and 95% used it more than once a week. Most people developed symptoms after more than two years of regular use, but the range was enormous: anywhere from four months to 27 years. About a third of patients in that study reported symptoms after less than one year of use. So there’s no safe threshold of use that guarantees you won’t develop it, and daily users are at the highest risk.
What Recovery Feels Like
Once you stop using cannabis entirely, the recovery phase brings a gradual return to normal. The vomiting stops, the morning nausea fades, appetite comes back, and the compulsive need for hot showers disappears. Complete and persistent resolution of all symptoms following cannabis cessation, sustained for at least 12 months, is considered the strongest evidence that what you experienced was CHS rather than another condition.
The catch is that resuming cannabis use almost always brings the symptoms back, often faster the second time around. Many people cycle through multiple episodes before making the connection between their cannabis use and their symptoms, partly because cannabis is widely known as an anti-nausea drug. The idea that it could be causing the exact symptom it’s supposed to treat makes CHS counterintuitive and easy to miss.
Physical Risks During Episodes
Beyond the misery of the vomiting itself, CHS episodes carry real physical consequences. Repeated forceful vomiting causes dehydration, which can become severe enough to affect kidney function. The sweating and inability to keep fluids down compound the fluid loss. Your heart rate and blood pressure can spike during episodes as your nervous system goes into overdrive. These aren’t just uncomfortable sensations. They’re signs your body is under significant stress, and severe episodes can require IV fluids and monitoring.