We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What are the Possible Causes of Unexplained Nausea?

By Erica Stratton
Updated Mar 03, 2024
Our promise to you
The Health Board is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At The Health Board, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Unexplained nausea can have so many causes. It can be a symptom of various undiagnosed diseases, a side effect of medication, or the first sign of a food allergy. Other times, the stomach is not receiving the nerve signals it needs in order to commence digesting properly.

Diagnosing nausea begins with eliminating the most common causes. If someone is on a certain kind of medication, they may be asked to go off it in order to discern if nausea is a side effect. Pregnancy and hunger are also causes of nausea that can take someone by surprise. Once these options have been ruled out, the doctor may ask the patient to keep a log of all her daily activities in order to determine the cause.

There are several chronic illnesses which have continual nausea as a little-known symptom. For example, diabetes can begin with nausea before any other obvious symptoms. Problems with the gallbladder can manifest themselves in a queasy stomach as well as a pain in the side. Acid reflux disease can have nausea as a main side effect.

Unexplained nausea can also happen as the result of a food allergy. Though food allergies are usually diagnosed when people are children, they can also develop later in life. Sometimes, a person will become allergic to a food he previously had no problems with. In these cases, a patient is often asked to start as bland a diet as possible, then keep a food diary as they add new items to the diet. When the person has a reaction to a new food, he will have found the cause of his unexplained nausea.

Nausea associated with chronic conditions can be misleading, because in absence of other symptoms, the main problem will seem to be gastric, rather than the symptom of a larger problem. Making an appointment with a doctor and working with a gastric specialist can help a sufferer sift through all of the probable causes to find a treatment.

Finally, unexplained nausea may not be caused by a disease or a food allergy, but by a nerve disorder. Some researchers refer to the stomach as having a "pacemaker," meaning that it receives nerve signals telling it whether or not to digest. Sometimes, the stomach can receive these messages when they're not needed or never receive them at all. When the stomach is "paralyzed" like this and unable to digest food, the patient often feels sick to her stomach. Treatments for this type of stomach problem are still being researched.

The Health Board is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By anon989838 — On Mar 24, 2015

My cousin is having unexplained vomiting. He vomits it out anything consumed orally. He is 70 years old. He was under neurological treatment but left the medicine off 15 days as advised by the physician. He has undergone an endoscopy and colonoscopy and the results are not indicative of any causes for vomiting. They are unable to find out the cause for the problem. What is next?

By anon970129 — On Sep 16, 2014

Unexplained nausea is also one of many warning signs for heart disease, hypoglycemia and various cancers. Just thought it was worth adding that.

By seefooddiet — On Mar 08, 2014

I've had unexplained illnesses and reactions all my life. I thought it could be food allergies, but the foods I ate could be totally O.K. some times and cause reactions at other times; it was unpredictable.

It's only this year that I finally found an answer: histamine intolerance. It's a weird thing because it can affect any part of the body, and it's inconsistent. The low histamine diet instantly fixed my digestive problems but took a bit longer to overcome my skin problems, but I can't tell you how happy I am not to have those pains and itches all the time.

The book I found it out from is called "Strictly Low Histamine," and I'd recommend it to anyone with unexplained sickness that appears to be food allergy. It might not be food allergy -- it might be histamine intolerance.

By serenesurface — On Apr 20, 2012

Great article, so informative!

Now that I think about it, I used to get nausea a lot and for no apparent reason several years before I was diagnosed with diabetes. I think it used to happen after having unhealthy foods and sweets. My blood sugar was probably soaring high and giving me nausea.

I actually noticed it when I went to the hospital for a glucose tolerance test. They made me drink 75 grams of pure glucose and about fifteen minutes later, I had the worst nausea and vomiting of my life. I used have a similar reaction when I ate too much junk food before.

I guess this was a sign of my diabetes but I never took it seriously. If I had gone to the doctor earlier, I might have been diagnosed much earlier.

By burcidi — On Apr 19, 2012

Last year, I started getting nausea all of the sudden, what seemed like for no reason. I had mild nausea throughout the day but vomited any time I was in a car, a bus or subway.

First I thought it was motion sickness but that didn't make sense because I've never had motion sickness before. I also didn't have a problem with my ears and I think motion sickness happens when the pressure inside the ears changes.

Anyway, after trying to ignore it for a couple of weeks, I finally went to the doctor. They did this breath test to see if there was any bad bacteria in my stomach. It came back positive! It turns out the bugs were making me sick! I was treated with antibiotics and the nausea disappeared.

By kylee07drg — On Apr 19, 2012

@StarJo – I guess antibiotics treat a wide range of infections. It would bother me not knowing what I had, but I would be glad for the relief if it worked.

I didn't go to a doctor when I started having unexplained nausea, because I had no other symptoms to tell him. I had just started my new job, and every morning at my desk, I would feel a powerful wave of nausea come over me.

A couple of times, I got up to go to the bathroom, thinking I would surely vomit soon. I didn't, and the nausea eventually passed.

I started drinking peppermint tea to soothe my stomach, and it worked. I now believe that I was just going through a really stressful time, and my stomach was in upheaval because of it.

By StarJo — On Apr 18, 2012

Nausea can mean that you have a bacterial infection. I had been ignoring subtle symptoms of a urinary tract infection, because I couldn't be sure if I had it or not. However, when the nausea arrived, I knew that something was wrong.

I woke up one morning extremely nauseated. Within a few minutes, I was vomiting. I decided to go see my doctor that day and figure out what was wrong.

I told him I suspected I might have a UTI, and he tested my urine but found no signs of it. He decided to give me antibiotics to treat whatever might be ailing me, and it worked. So, I had some type of infection somewhere in my body.

By lighth0se33 — On Apr 17, 2012

My aunt had waves of nausea come over her suddenly for seemingly no reason. Since her mother and grandmother both had developed diabetes later in life, the doctor decided to test her for it.

She did have it, after all. This was terrible news to her, because now, she has to watch everything she eats and monitor her blood sugar levels. She has had to give up so many of her favorite foods, and this has made her depressed and irritable at times.

However, I know that she is probably healthier because of it. She ate way too much sugar and fatty foods before, and she was overweight. She will probably finally be able to lose the weight now.

By orangey03 — On Apr 17, 2012

My husband discovered that he was allergic to mushrooms after eating a dish containing them a couple of times and having the same reaction. He suffered hot flashes and nausea, and this later turned into violent diarrhea.

The first time it happened, he thought he might have food poisoning, because he had eaten at a restaurant and did not know how the food had been stored and prepared. The second time, though, he had eaten a meal his sister had made for him, and he knew that the food was good. This led him to determine he was allergic to mushrooms.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.