9 Signs That Your Stomach Issues May Not Be IBS

Digestive symptoms are common in people with irritable bowel syndrome (IBS). This often includes:

Still, it can be hard to know if these symptoms are because of IBS. It could be something as simple as a food intolerance, or it could be a more serious condition.

Certain symptoms may suggest a health problem other than IBS. These symptoms don't necessarily mean you don't have IBS. If you have them, though, it is a good idea to talk to your doctor.

Tell your doctor about any symptoms you have on a regular basis, even if they are not on this list.

This article looks at some of the symptoms that may be related to a health problem other than IBS.


Gas and Bloating Within 90 Minutes of Eating

Stomach ache
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Intestinal gas and bloating are common IBS symptoms. The timing of the these symptoms, though, is important.

Carbohydrates are substances in food that provide your body with energy. They include sugars, starches, and fiber. It usually takes about 90 minutes for undigested carbohydrates to reach your large intestine.

Once there, gut bacteria start breaking them down. This is called fermentation. Fermentation produces gas.

You should not start to feel gassy before that 90-minute mark. If you do, it could be because you have too much bacteria in your small intestine.

This condition is called small intestinal bacterial overgrowth (SIBO). SIBO is diagnosed with a hydrogen breath test. It can be treated with select antibiotics.

If you experience gas and bloating within 1.5 hours of eating, talk to your doctor. This doesn't necessarily mean your doctor was wrong about your IBS. It just means it might be worthwhile to be tested for SIBO.


Diarrhea Right After Eating

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Frequent bouts of diarrhea are a common IBS symptom. This symptom is also common with inflammatory bowel disease (IBD), a group of conditions that cause inflammation of the intestines. It is also seen in celiac disease, which is an immune reaction to a protein found in wheat and other grains.

The simple act of eating can cause contractions in your intestines. This can lead to diarrhea.

A couple of other conditions could also cause this symptom. These conditions are less common. If you have a sudden, immediate diarrhea right after eating, talk to your doctor. Your doctor may want to consider:

These conditions are relatively rare. It is still possible that diarrhea after eating is a symptom of your IBS. Still, it may be a good idea to talk to your doctor about other possibilities.


Pain Unrelated to Bowel Movements

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In people with IBS, the criteria for diagnosis says abdominal pain should be related to bowel movements.

Many IBS patients say this is not always true. But for the most part, people with IBS feel like their pain has something to do with their diarrhea or constipation.

If you have pain you don't think is related to your bowel movements, talk to your doctor. It may still be IBS, but it is worth looking at other possibilities.

If you have an IBS diagnosis but you think your pain is not typical of IBS, talk to your doctor at once. Persistent pain should always be evaluated by a doctor.


Symptoms Set Off by Eating Wheat

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Gluten is a protein found in wheat and some other grains. For many people, foods that contain gluten can cause IBS-like symptoms.

That is why doctors recommend that people with IBS should also be tested for celiac disease. This test is only conclusive if you are eating foods that contain gluten.

Celiac disease can cause other serious health problems, so it is important to know if you have it.

Even if you do not have celiac disease, eating wheat may trigger IBS symptoms. You may have a condition known as non-celiac gluten sensitivity.

You may also be reacting to fructan, a kind of carbohydrate found in grains and some fruits and vegetables. Your doctor can guide you through an elimination diet to determine if any foods are triggering your symptoms.


Blood in Stools

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Blood on or in the stool is not a symptom of IBS. Sometimes blood in the stool comes from hemorrhoids. Hemorrhoids are swollen veins that can develop in your anus and lower rectum. 

Blood in the stool can also be a symptom of other more serious problems. This includes IBD or colon cancer.

If you see blood in the toilet after a bowel movement and it is not menstrual blood, see a doctor as soon as possible.


Vomiting on a Regular Basis

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Vomiting is not a symptom of IBS. When people who have IBS experience nausea and vomiting, it is not because of their IBS.

There are many health conditions that can cause vomiting.

If you experience frequent vomiting, tell your doctor. If you are having uncontrollable vomiting or are vomiting up blood, see a doctor at once.

Vomiting that does not happen with other signs of disease could be a condition called cyclic vomiting disorder (CVS). If you have vomiting without other symptoms, talk to your doctor.


Unexplained Weight Loss

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IBS may cause some weight loss, especially if you avoid food for fear of triggering symptoms. Significant, unexplained weight loss, though, is not a symptom of IBS. If you have this kind of weight loss, it may be a symptom of a more serious health problem.

If you have a poor appetite and it is not because you're afraid of eating trigger foods, see a doctor. This is not an IBS symptom.


Running Fevers

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IBS should not cause you to run a fever. Recurrent fevers have other causes, including:

  • Infections
  • Inflammatory conditions
  • Autoimmune conditions, when your immune system attacks healthy tissue by mistake
  • Cancer

If you experience recurrent fevers, talk to your doctor right away.


Deep, Persistent Fatigue

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Fatigue is not the same thing as feeling sleepy. Fatigue is extreme tiredness that can be both physical and emotional.

Many people with IBS say they often lack energy. Fatigue, though, is not a symptom of IBS. If you have deep, persistent feelings of fatigue, let your doctor know.


Symptoms of IBS can include abdominal pain, gas, bloating, and diarrhea and/or constipation. Other symptoms may be related to a different condition.

If you have gas and bloating within 90 minutes of eating, diarrhea right after you eat, or pain that does not seem related to your bowel movements, talk to your doctor. 

People who get IBS-like symptoms after eating wheat and other foods that contain gluten should be tested for celiac disease.

Other symptoms that are not associated with IBS include blood in the stool, frequent vomiting, unexplained weight loss, fever, and fatigue. If you have any of these symptoms, see a doctor right away.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Soares RLS. Irritable bowel syndrome, food intolerance and non-celiac gluten sensitivity. a new clinical challenge. Arq Gastroenterol. 2018;55(4):417-422. doi:10.1590/S0004-2803.201800000-88

  3. Fakhoury M, Negrulj R, Mooranian A, Al-Salami H. Inflammatory bowel disease: clinical aspects and treatments. J Inflamm Res. 2014;7:113-20. doi:10.2147/JIR.S65979

  4. Bhandari S, Jha P, Thakur A, Kar A, Gerdes H, Venkatesan T. Cyclic vomiting syndrome: epidemiology, diagnosis, and treatment. Clin Auton Res. 2018;28(2):203-209. doi:10.1007/s10286-018-0506-2

Additional Reading
  • Minocha A, Adamec C. The Encyclopedia of the Digestive System and Digestive Disorders (2nd Ed). New York: Facts on File; 2011.