13 Causes of Nausea—Besides a Typical Stomach Bug

You know the feeling: Your stomach starts churning, you begin swallowing a little harder, and you automatically make a mental map of the nearest bathrooms—just in case.

Nausea can strike anytime, anywhere—and when it does, you quickly start retracing your steps: What you ate, if you've been around anyone who was sick, and, for some people, when your last period was. But aside from gastroenteritis and expecting a child, nausea can be caused by many other things. Here are 13 other common (but still surprising) causes of nausea—and how to feel better.

Anxiety

Nausea can be a common symptom of anxiety. According to a 2022 review published in China Life Sciences, here's what happens: When you're in the throes of a panic attack, your body shifts into "fight-or-flight" mode. Adrenaline is pumped into your bloodstream, preparing you to take on a major physical challenge—like running or climbing.

In the meantime, bodily functions like digestion come to a virtual standstill, which leads to the accumulation of certain toxins in the body, Dr. Eugene Vaynkof, a family medicine physician at Integrated Medical Alliance in New Jersey, explained to Health. Eventually, chemical signals reach your brain and spark the sensation of nausea, Dr. Vaynkof said.

Diabetic Ketoacidosis

Nausea, vomiting, and abdominal pain? Classic signs of a stomach bug. But these same symptoms can be a red flag for a serious complication of type 1 diabetes, said endocrinologist Elizabeth Holt, MD, assistant consulting professor of medicine at Duke University School of Medicine. According to a 2022 review in Critical Care Nursing Quarterly, diabetic ketoacidosis occurs when the body doesn't produce enough insulin. The cells begin burning fat for fuel, causing high levels of chemicals called ketones to build up in urine and blood. People start to feel bad and get nauseated when they go into ketoacidosis, Dr. Holt said.

The condition can lead to coma or death, especially in people who don't know they have diabetes or don't recognize the warning signs, such as extreme thirst and frequent urination.

Adrenal Insufficiency

This hormonal disorder means your adrenal glands, which are right above your kidneys, can't produce high enough amounts of certain hormones. One cause of adrenal insufficiency is Addison's disease, an autoimmune disease that damages the adrenals and limits the production of cortisol, a vital hormone for growth, metabolism, and other functions.

How do you know if your adrenals aren't working properly? "The classic symptoms are nausea, vomiting, diarrhea, weight loss, and, if it continues, your blood pressure goes down so much you go into shock," Dr. Holt said. People with adrenal insufficiency who experience these symptoms should seek immediate medical attention; without treatment, the condition can be deadly.

Heart Attack

Beware of nausea or a sick feeling in your stomach–even if you don't have chest pain. It could mean you're having a heart attack.

Women are more likely to report these less typical cardiac symptoms than men, said Amnon Beniaminovitz, MD, a cardiologist at Manhattan Cardiology in New York City. Dr. Beniaminovitz told Health that he'd had patients who present with acid reflux-like symptoms who were actually having heart attacks, so it's really important to get checked out.

"Sometimes the pain of heart attack is described as stomach pain, or pain in the middle of the upper abdomen," Dr. Beniaminovitz said. Rather than a sharp, stabbing pain, it can feel more like "discomfort or heaviness" or even indigestion.

Acid Reflux

Heartburn is the hallmark of acid reflux and GERD (gastroesophageal reflux disease). But fiery pain in your chest or abdomen isn't the only symptom. When stomach acid or stomach contents churn back into the esophagus, some people experience nausea.

Dr. Beniaminovitz told Health about a 26-year-old male who came in with nausea and discomfort, symptoms that can signal a possible heart attack. After a thorough workup ruled out a cardiac cause, the young man's problem was easily remedied with over-the-counter proton pump inhibitors, Dr. Beniaminovitz said.

Gastroparesis

Nausea is among the unpleasant symptoms accompanying gastroparesis, a potentially debilitating digestive disorder. For various reasons (sometimes a complication of diabetes), the movement of food from the stomach to small intestine slows down.

"Food sits around in your stomach–warm and dark and moist–and ferments," said Virginia Beach-based gastroenterologist Patricia Raymond, MD, assistant professor of clinical internal medicine at Eastern Virginia Medical School.

Foreign Body Ingestion

You'd likely know if you swallowed something you weren't supposed to. But then again, you might not: It's easy to accidentally gulp down small fish bones from a salmon dinner or a wire barbecue brush bristle that gets stuck to the grill and embedded in a burger. That foreign body in your stomach can lead to nausea, vomiting, and abdominal pain.

Another less common reason for eating things that aren't food—pica, which is a disorder that causes people to swallow non-food items intentionally. According to a 2022 research article published in Epidemiology and Psychiatric Sciences, this can result from a psychiatric condition or iron deficiency.

Gallbladder Disease

Sudden right-side abdominal pain after a meal of greasy or fatty food is a classic description of a gallbladder attack. The pain usually strikes when hard particles, called gallstones, block ducts that carry bile (which aids digestion). Occasionally, though, people with gallbladder problems just have nausea, Dr. Raymond said.

Whether it's pain or nausea that's bothering you, don't assume you're "out of the woods" if stones don't show up on an ultrasound, Dr. Raymond added. Other imaging tests can assess gallbladder function, which may reveal trouble with your bile-storing organ. Sometimes, Dr. Raymond said, "we discover that it's inflamed and thick and ugly." If gallstones aren't causing that queasiness, inflammation, infection, excessive alcohol consumption, or even a tumor may be to blame.

Cyclical Vomiting Syndrome

This scary syndrome, which is more common among children but affects adults too, causes sudden, repeated attacks of severe nausea and vomiting for no apparent reason. A single episode can last for hours or days.

"Mild nausea is not the way you would describe these people," Dr. Raymond said. "They're just laid low by this."

While the cause is unclear, research, such as a 2021 research article published in the Journal of Child Neurology, reveals an association between cyclical vomiting syndrome and migraines–even simply a family history of the intense headaches. Patients are typically treated with migraine medicine.

Vasovagal Syncope

Pale and nauseous at the sight of blood? That uneasy feeling–and subsequent fainting–is vasovagal syncope, a brief loss of consciousness also called "passing out."

A cascade of symptoms occurs when some trigger stimulates the vagus nerve, which controls involuntary body functions. "When it is over-stimulated, it can cause the feeling of nausea," Dr. Beniaminovitz said.

Triggers such as pain, anxiety, prolonged standing, and straining to have a bowel movement can all lead to a sudden drop in heart rate and blood pressure. Before blacking out, people can feel lightheaded and queasy, and they may have heart palpitations. Other symptoms include a clammy or sweaty feeling, ringing in the ears, or blurred or tunnel vision.

Prescription Medications

A 2015 review article published in Histopathology explained that plenty of prescription and over-the-counter medications carry nausea as a side effect. These include oral bisphosphonates for osteoporosis and injectable diabetes medicines that control blood sugar by slowing digestion. Some blood pressure drugs, antidepressants, and antibiotics can also cause nausea. Talk to the prescribing doctor if you're on any of these medications and experience queasiness.

OTC Painkillers or Supplements

Even common pain relievers like aspirin, ibuprofen, and naproxen, known as nonsteroidal anti-inflammatory drugs (NSAIDs), can cause nausea (as well as a risk of erosion of the lining of the stomach and bleeding.)

"In the time that they sit on the surface of the stomach, which is anywhere between a half-hour and an hour, they can cause significant irritation," said doctor of pharmacy Patrick Meek, associate professor at the Albany College of Pharmacy and Health Sciences. Take them with food to avoid nausea, or look for "enteric-coated" versions that help protect the stomach.

Certain vitamins and supplements should also be taken with food to avoid queasiness. Iron and vitamin C in particular can upset your stomach. "They have a local irritating effect just because of the formulations, but as soon as they pass the stomach, those symptoms tend to subside," Meek said.

Cannabinoid Hyperemesis Syndrome

Smoking marijuana, which some people do to relieve nausea, may have the opposite effect.

As marijuana has been legalized in more states, hospital emergency rooms have seen more and more cases of cannabinoid hyperemesis syndrome, a condition linked to medical or recreational pot use that causes bouts of severe nausea and vomiting, as described in a 2016 case report and review published in British Medical Journal Case Reports. "You can get hospitalized for retching that's so severe that you tear your esophagus," Dr. Raymond said.

Scientists don't yet know why this happens, but quitting cannabis seems to resolve symptoms in most patients, according to the case report.