Repeated vomiting usually points to one of a handful of common causes: a stomach bug, food poisoning, pregnancy, medication side effects, or a digestive condition that slows your stomach’s ability to empty. When vomiting keeps coming back over days or weeks without an obvious explanation like illness or bad food, it signals something your body needs you to pay attention to.
The causes range from straightforward to surprising. Some are easy to fix on your own, while others need a doctor’s help to sort out. Here’s what could be going on.
Short-Term Causes That Usually Resolve
The most common reason for a few days of vomiting is a stomach virus (gastroenteritis) or food poisoning. These typically clear up within one to three days. Food poisoning tends to hit faster, often within hours of eating contaminated food, while a stomach virus builds more gradually. Both cause nausea, vomiting, and sometimes diarrhea. If you’re in this window, your main job is staying hydrated and waiting it out.
Medications are another frequent culprit. Antibiotics, painkillers, chemotherapy drugs, and even some supplements (especially iron) can trigger nausea and vomiting. If you recently started a new medication and the vomiting followed, that connection is worth exploring with whoever prescribed it.
Pregnancy-related nausea affects up to 80% of pregnant people and can start as early as four weeks in. Despite the name “morning sickness,” it can happen any time of day and persist well into the second trimester.
When Your Stomach Empties Too Slowly
Gastroparesis is a condition where your stomach takes much longer than normal to push food into your small intestine. The result is nausea, vomiting (sometimes of food eaten hours earlier), bloating, and feeling full after just a few bites. It’s one of the more common reasons for vomiting that keeps happening without an obvious cause.
Diabetes is the leading known cause of gastroparesis, because high blood sugar over time can damage the nerve that controls stomach contractions. But in many cases, no clear cause is found. To diagnose it, doctors use a gastric emptying scan: you eat a small meal containing a harmless radioactive tracer, then a camera tracks how quickly your stomach processes it over about four hours. There’s also a breath test version and a swallowable capsule (called a SmartPill) that travels your entire digestive tract and sends data to a small recorder you wear.
Cyclic Vomiting Syndrome
If your vomiting comes in intense episodes that seem to follow a pattern, with stretches of feeling completely fine in between, you may have cyclic vomiting syndrome (CVS). This condition causes bouts of severe nausea and vomiting that start suddenly, last less than a week, and then disappear entirely until the next episode. The formal criteria require at least three episodes in the past year with at least two in the past six months, separated by at least a week of no symptoms.
CVS is closely related to migraines. Many people with CVS also get migraine headaches, and the same triggers often set off both: stress, sleep deprivation, certain foods, and menstrual cycles. It tends to be more common in younger adults and is often misdiagnosed for years because the episodes look like food poisoning or stomach bugs to emergency room doctors who only see the person once.
Cannabis and Vomiting
This one surprises a lot of people. Cannabinoid hyperemesis syndrome (CHS) causes cycles of intense nausea, vomiting, and abdominal pain in people who have used marijuana regularly for a long time, often years. It’s counterintuitive because cannabis is widely known for reducing nausea, but in some long-term users, it has the opposite effect.
The hallmark sign of CHS is a compulsive urge to take hot showers or baths, which temporarily relieve the symptoms. Some people spend hours a day in the shower during an episode. The condition has three phases: a prodromal phase with morning nausea and stomach pain that can last months or years, a hyperemetic phase with overwhelming vomiting lasting 24 to 48 hours, and a recovery phase. The only effective treatment is stopping cannabis use entirely. When people quit, symptoms gradually disappear over days to months.
CHS is increasingly common in emergency rooms, and patients with it tend to be older than those with cyclic vomiting syndrome and are more likely to show signs of dehydration on blood work, including low potassium and elevated kidney markers.
Stress, Anxiety, and the Gut-Brain Connection
Your brain and your gut are in constant communication, and emotional distress can directly trigger vomiting. Psychogenic vomiting refers to persistent or recurrent vomiting driven by psychological mechanisms rather than a structural problem in your digestive tract. Anxiety, panic, chronic stress, and major life changes are common triggers.
This isn’t “all in your head” in the dismissive sense. Research shows that most people with stress-related vomiting actually have measurable changes in how their stomach moves and how sensitive it is to stimulation. Pain and anxiety pathways in the brain directly influence the vomiting center, and everyone has a threshold at which psychological stress can provoke vomiting. For some people, that threshold is lower, especially if they also have underlying gut sensitivity.
One important distinction: standard anti-nausea medications typically don’t work well for psychogenic vomiting. Treatment usually involves addressing the underlying anxiety or stress through therapy, sometimes with medications that target anxiety or mood rather than the stomach itself.
Abdominal Migraines
Most people associate migraines with headaches, but migraines can also target the gut. Abdominal migraines cause episodes of moderate to severe belly pain (usually around the belly button or hard to pinpoint), along with nausea, vomiting, loss of appetite, and pale skin. Episodes last anywhere from 2 to 72 hours and then resolve completely, with no symptoms between attacks.
While this diagnosis is most common in children, adults get them too, and many adults with abdominal migraines also develop traditional migraine headaches. If your vomiting episodes come with dull abdominal pain and you have a personal or family history of migraines, this is worth mentioning to your doctor.
How to Manage Vomiting at Home
Dehydration is the biggest immediate risk from repeated vomiting. The most effective rehydration approach is to take very small sips frequently rather than gulping large amounts, which often triggers more vomiting. Start with about a teaspoon (5 mL) of fluid every five minutes, then gradually increase. Oral rehydration solutions are better than plain water because they replace the sodium and potassium you lose when you vomit. For each episode of vomiting, aim to replace roughly 2 mL per kilogram of your body weight in additional fluid.
Avoid solid food until you can keep liquids down consistently. When you reintroduce food, start bland: toast, rice, bananas, plain crackers. Skip anything fatty, spicy, or dairy-heavy for the first day or two.
Signs You Need Immediate Help
Most vomiting resolves on its own, but certain warning signs mean you should get medical attention quickly. Vomiting blood or material that looks like coffee grounds, black or bloody stool, severe abdominal pain, confusion or unusual drowsiness, inability to keep any fluids down for more than 12 hours, or signs of significant dehydration (rapid heart rate, dizziness when standing, very dark urine, or no urination for eight or more hours) all warrant urgent evaluation.
Severe dehydration from prolonged vomiting can cause a dangerous drop in blood volume, leading to a condition called hypovolemic shock where blood pressure falls and organs don’t get enough oxygen. This is rare, but it’s why persistent vomiting with no fluid intake is not something to push through indefinitely.
Getting Answers for Ongoing Vomiting
If you’ve been vomiting repeatedly for more than a week, or if episodes keep coming back without a clear explanation, doctors will typically start with blood work to check for metabolic problems (like diabetic ketoacidosis or electrolyte imbalances) and may order an upper endoscopy. This involves a thin, flexible camera passed through your mouth into your stomach and upper intestine to look for ulcers, inflammation, infections like H. pylori, or structural problems. It’s one of the first tests considered for vomiting that can’t be explained by an obvious short-term illness.
Keeping a log of your episodes helps enormously. Track when the vomiting happens, what you ate beforehand, your stress level, any substances you used (including cannabis), whether hot showers help, and how long each episode lasts. These details can point toward patterns that distinguish conditions like CVS, CHS, or abdominal migraines from each other, often saving months of unnecessary testing.