How Do You Know If You Have IBS? (Diagnosis Steps)

Self-Diagnosis Could Lead to Delayed Treatment

If you have symptoms that could point to irritable bowel syndrome (IBS), the first thing to do is work toward getting an accurate diagnosis. That can take time, several healthcare provider visits, and lots of tests.

Many different conditions cause similar symptoms to IBS, including abdominal cramps, bloating, gas, diarrhea, constipation, or a mix of the two. Proper treatment requires a thorough diagnostic process.

This article discusses how to know if you have IBS, the diagnostic process, and treatments for IBS.

Man in suit and tie holding stomach in discomfort
Hill Creek Pictures / UpperCut Images / Getty Images

Things that might help you zero in on a diagnosis include:

  • Compare your symptoms with those typical of IBS
  • Keep symptom and food logs
  • Discuss your logs with a healthcare provider
  • See a digestive specialist (if necessary)
  • Have tests to determine the cause of your symptoms

What IBS Is and Isn’t

IBS is a functional disorder of the colon (large intestine) that causes crampy abdominal pain, bloating, constipation and/or diarrhea. IBS is not the occasional bout of diarrhea that resolves on its own. Rather, IBS is a chronic condition with symptoms that don't resolve on their own, or are worsened by particular stimuli or “triggers.”

IBS is not ulcerative colitis or Crohn's disease. IBS will not increase your risk of colon cancer nor will it cause blood in the stool. IBS is known as a functional gastrointestinal disorder because no structural or biochemical cause can be found to explain the symptoms—the colon shows no evidence of disease, such as ulcers or inflammation.

Other conditions that may be confused with IBS include lactose intolerance, celiac disease, and diverticulitis.

Food and Symptom Logs

Start by keeping a log of your digestive symptoms and a food diary. Logs are more effective than memory in helping describe symptoms to a healthcare provider. They can also help you spot patterns. Lots of smartphone apps can help you track food and symptoms.

Next, bring your logs to your regular healthcare provider. They may be able to diagnose you, or they may refer you to a digestive system specialist—a gastroenterologist.

IBS Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Man

Getting a Diagnosis

A gastroenterologist will take a careful history of any IBS symptoms, as well as conduct some tests. During the diagnostic process, they'll likely keep in mind the Rome Criteria and possibly guidelines from the American College of Gastroenterology (ACG).

  • Rome Criteria: The Rome Criteria outlines symptoms and applies parameters such as frequency and duration of symptoms to diagnose IBS. These are updated regularly and reflect the latest thinking about IBS symptoms.
  • ACG Guidelines: Released in 2021, these guidelines suggest a new way of diagnosing IBS that does away with a "diagnosis of exclusion" in favor of a "positive diagnosis," saying it can save time and get you started on treatment faster.

What Is a Diagnosis of Exclusion?

A diagnosis of exclusion is a process by which healthcare providers rule out other potential causes of symptoms before making a diagnosis. It's the opposite of a positive diagnosis, which involves looking for indicators of a condition rather than what it isn't.

The IBS diagnosis-of-exclusion process typically involves a slate of diagnostic tests to rule out other possible digestive disorders, infection, bacterial overgrowth, or colitis. Tests include:

  • Rectal exam: During a rectal exam, the healthcare provider inserts a lubricated, gloved finger into the rectum to feel for abnormal areas and check for bleeding.
  • Stool culture: A stool sample is analyzed for bacterial infection, parasites, or other possible causes of diarrhea.
  • Sigmoidoscopy: A flexible viewing tube called a sigmoidoscope is inserted through the rectum to examine the lowest one-third of the large intestine, which includes the rectum and sigmoid colon.
  • Colonoscopy: A colonoscope, which is a flexible tube with lenses, a tiny camera, and a light at the end, is inserted through the rectum to examine the inside of the colon beyond the areas a sigmoidoscopy can reach.

The recommendations for a positive diagnosis include:

  • Looking at your family and personal medical history
  • A physical exam to check for other causes
  • Evaluation of symptoms to see if they're consistent with IBS (abdominal pain and altered bowel habits for six months or longer, with no "alarm" features of other conditions)
  • Minimal diagnostic testing, which varies based on symptoms

Beginning Treatment

If you're diagnosed with IBS, it's time to come up with a treatment plan. That may include dietary and lifestyle changes, medication, and complementary therapies.

Dietary Changes

Dietary changes are important because the majority of patients with IBS has their own specific set of trigger foods. Some of the more common triggers include:

  • Alcohol
  • Artificial sweeteners
  • Artificial fat (olestra)
  • Carbonated beverages
  • Coconut milk
  • Coffee
  • Dairy
  • Egg yolks
  • Fried foods
  • Oils
  • Poultry skin and dark meat
  • Red meat
  • Shortening
  • Solid chocolate

An eating plan that's getting a lot of attention for people with IBS is the low-FODMAP diet, which limits a group of sugars that are hard for the body to digest. The ACG guidelines recommend a limited trial of this diet.

However, the ACG guidelines recommend against against testing for food allergy and food sensitivity in all patients with IBS unless symptoms are reproducible and concerning for food allergy.

Lifestyle Changes

Stress doesn’t cause IBS, but it can make IBS symptoms worse. Eliminating stressful situations and learning to control stress when it does occur may help you alleviate symptoms and feel better.

Your healthcare provider may also recommend:

  • Losing weight
  • Stopping smoking
  • Getting regular exercise


Several medications can be used to treat IBS symptoms. IBS drugs have different mechanisms of action, but none of them is a cure, and you may have to try several before finding one that helps symptoms. Some of the ACG-recommended drugs include:

  • Amitiza (lubiprostone)
  • Linzess (linaclotide)
  • Trulance (plecantide)
  • Zelnorm (tegaserod)
  • Xifaxin (rifaximin)
  • Tricyclic antidepressants
  • Mixed opioid agonists/antagonists

Complementary Therapy 

Complementary therapies can include anything from supplements to support groups. Some supplements that may have an effect on IBS include:

The ACG guidelines recommend soluble fiber and peppermint oil while recommending against acidophilus and other probiotics.

Other complementary therapies that have shown some effectiveness for IBS include:

  • Hypnosis
  • Cognitive-behavioral therapy (ACG recommended)
  • Biofeedback

While these treatments don't address physiological problems, they can help you deal with the stresses of having a chronic illness and establishing good habits for managing it.

A Word From Verywell

IBS is a complicated condition and, in some cases, it can take time to get a proper diagnosis. However, once the diagnosis is in place, you have a lot of options for managing symptoms. Not every treatment works for every person, so expect some trial and error as you explore the different options.

Frequently Asked Questions

  • What are the symptoms of IBS?

    Symptoms of IBS include abdominal cramps, bloating, diarrhea, constipation, excessive gas, and mucus in your stool. 

  • Can you self diagnose IBS?

    No, IBS is a diagnosis of exclusion. That means your doctor needs to rule out other potential causes of your symptoms before determining it is IBS. Self-diagnosis can lead to delayed treatment or the wrong medicine.

  • What are three types of IBS?

    There are three main types of IBS. IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), and mixed IBS with alternating constipation and diarrhea (IBS-M).

  • What foods trigger IBS?

    Common foods that can trigger IBS symptoms include alcohol, artificial sweeteners, artificial fat, carbonated beverages, coffee, dairy, fried foods, oils, fatty cuts of meat, and chocolate. 

7 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.
  1. International Foundation for Gastrointestinal Disorders. Symptom diary.

  2. Lacy BE, Patel NK. Rome criteria and a diagnostic approach to irritable bowel syndrome. J Clin Med. 2017;6(11). doi:10.3390/jcm6110099

  3. Lacy BE, Pimentel M, Brenner DM, et al. ACG clinical guideline: Management of irritable bowel syndrome. Am J Gastroenterol. 2021;116(1):17-44. doi:10.14309/ajg.0000000000001036

  4. Harvard Medical School. Try a FODMAPs diet to manage irritable bowel syndrome.

  5. Camilleri M, Ford AC. Pharmacotherapy for irritable bowel syndrome. J Clin Med. 2017;6(11). doi:10.3390/jcm6110101

  6. Harvard Medical School. Using alternative and complementary treatments to manage IBS.

  7. Cleveland Clinic. Irritable Bowel Syndrome (IBS).

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.