IBS

What Is Irritable Bowel Syndrome (IBS)? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Linda Thrasybule
By Medically Reviewed by 
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Medically Reviewed
Irritable bowel syndrome (IBS) is a gastrointestinal disorder that affects the small and large intestines, causing symptoms like abdominal cramping and changes to normal bowel habits.

IBS is considered a disorder of gut-brain interaction, causing communication issues between your brain and intestines, and leading to increased sensitivity and muscle contractions in your gut.

IBS doesn’t cause permanent harm to the digestive tract, nor does it increase the risk for colorectal cancer, unlike inflammatory bowel disease (IBD), which is sometimes confused with IBS but is an entirely different disorder. Still, IBS can be frustrating and even debilitating at times, affecting a person’s physical, emotional, and social well-being.

Signs and Symptoms of Irritable Bowel Syndrome

IBS symptoms can include:

But not all IBS is the same. There are several types:

  1. IBS with diarrhea (IBS-D), which may involve loose, watery stools
  2. IBS with constipation (IBS-C), which may involve stools that are lumpy and hard
  3. IBS with mixed bowel habits (IBS-M), which includes both diarrhea and constipation symptoms

Causes and Risk Factors of Irritable Bowel Syndrome

Researchers don’t know exactly why some people get IBS, but they speculate that stress in early life, changes in microbes found in the gut, and nerve irregularities in your gut may play a role.

The Brain and Gut Connection

Millions of nerve cells reside in the lining of the GI tract, almost like a second brain. It is called the enteric nervous system, and it controls digestion and tells the bowels when to contract, move, and secrete fluids. There’s emerging evidence that the brain and gut communicate through this major network of nerves.

“When we describe our emotions, we tend to say that we feel sickened or nauseated, or [it is] gut-wrenching, which makes sense since our emotions seem to occur from our gut,” says Judith Scheman, PhD, the director of behavioral medicine at Cleveland Clinic’s Digestive Disease and Surgery Institute in Ohio.

Some experts think that IBS is caused when there’s a glitch in that communication. “We all respond to stress physically, and some of us physically react with our gut, as with diarrhea or constipation, while others get headaches or back pain,” Dr. Scheman says.

The problem is that the stress response in the gut can create a vicious cycle, in which the stress causes symptoms and vice versa, also known as a feedback loop. “Each time you go around it gets worse, like a downward spiral,” Scheman says.

An Imbalance of Microbes in the Gut

Millions of microbes populate the gut, and while they normally protect against infection and help the immune system, studies suggest that imbalances can result in IBS.

Viral or bacterial infections that affect your gastrointestinal tract, such as gastroenteritis, salmonella, Escherichia coli (E. coli), and Clostridioides difficile (C. diff) can result in post-infectious IBS, or IBS-like symptoms that appear after the infection itself has gone away. For most people, post-infectious IBS is temporary, but symptoms can last from several weeks to a year.

Other studies show that some people with IBS also have small intestinal bacterial overgrowth (SIBO), a condition involving an overgrowth of bacteria in the small intestine that causes bloating, stomach pain, and excessive gas. A review published in March 2017 in the journal Gut and Liver found that 4 to 78 percent of people with IBS also had SIBO.

Antibiotics and nutritional interventions, such as supplements and a lactose-free diet, can help reduce symptoms of SIBO.

Risk Factors for IBS

IBS can strike at any age, but people younger than 50 are more likely to develop it. The chances of developing IBS increase if you have a family member with IBS.

Women are more likely to develop it than men. Although the reason is still up for debate, some research suggests that sex hormones, particularly estrogen and progesterone, also reside in the digestive tract and can contribute to IBS flare-ups.

There’s also evidence that people with IBS tend to suffer from mood disorders such as depression or anxiety. “There is a high overlap between the two,” says Jeffrey Baumgardner, MD, a gastroenterologist in Santa Rosa, California. “A significant number of people with IBS also have a history of some kind of abuse — emotional, physical, or sexual.”

Dr. Baumgardner also thinks that IBS has something to do with how people process stress, though research hasn’t shown why yet.

Potential Triggers of Irritable Bowel Syndrome

Just as IBS varies from person to person, IBS symptoms can be triggered by a number of factors, including:

  • Certain foods or food ingredients such as milk and dairy products, citrus fruits, cabbage, wheat, and carbonated beverages.
  • Stress: While not a direct cause of symptoms, research suggests it may aggravate symptoms, causing them to be more severe and frequent.
  • Hormones: Taking estrogen therapy before or after menopause increases your risk of IBS.

While it may take some trial and error to figure out what’s causing symptoms, your doctor can help you manage them.

Learn More About Triggers for Irritable Bowel Syndrome

Quiz: IBS vs. IBD

Christina Vogt
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How Is Irritable Bowel Syndrome Diagnosed?

Although there is no standard test to diagnose IBS, your doctor will likely perform tests such as blood or stool tests, upper GI endoscopy, or colonoscopy to rule out serious conditions such as celiac disease, IBD, and colon cancer.

Once other conditions are ruled out, doctors often use the guidelines known as the Rome criteria, which are a set of symptom criteria that help doctors give an accurate IBS diagnosis.



According to the latest revision, the Rome IV, symptoms such as abdominal pain should occur, on average, at least one day per week within the previous three months, accompanied by at least two of the following other symptoms:

  • Abdominal pain related to a bowel movement
  • Changes in the frequency of stools
  • Changes in the appearance of stools

Duration of Irritable Bowel Syndrome

IBS is a chronic condition that requires long-term management. But finding the right treatment and lifestyle modifications can help keep symptoms under control.

Treatment and Medication Options for Irritable Bowel Syndrome

There’s no one-size-fits-all treatment for IBS. Most people with IBS try different treatments before they find one or a combination of a few that work. One way to start is to develop a sense of how your IBS affects your diet, mood, and stress level, as well as other areas of your life.

Your doctor will likely recommend the following strategies:

  • Dietary changes
  • Medications
  • Psychotherapy (talk therapy)
  • Complementary and integrative medicine approaches like acupuncture and meditative techniques

Depending on your symptoms, any combination of these options may be part of your treatment strategy.

Medication Options

Your doctor may recommend fiber supplements for constipation. In its 2021 clinical guideline for the management of IBS, the American College of Gastroenterology (ACG) recommends soluble fiber (but not insoluble fiber) to help manage IBS symptoms.

A few medications have been specifically approved for certain people with IBS.

For diarrhea:

For constipation:

Antidepressants may also be prescribed, particularly if you have depression and abdominal pain.

Alternative and Complementary Therapies

Emerging evidence suggests that acupuncture, yoga, and mindfulness meditation — which help reduce stress — can be helpful in easing IBS symptoms.

Another way to manage stress is through cognitive behavioral therapy (CBT), a form of psychotherapy that focuses on symptom-related worry. CBT targets the brain-gut connection, which is considered a key contributor to IBS symptoms.

RELATED: Can Cognitive Behavioral Therapy Help With IBS?

Gut-directed hypnotherapy — which aims to alter your body's responses to IBS symptoms by making the gut less reactive to emotional upheaval and stress and changing how the brain interprets signals from the gut — has shown promising results in research.

Modifying Your Diet

For people with IBS, figuring out which foods tend to cause symptoms can be tricky. A food diary may help you identify foods you should avoid.

Adhering to diets like the low-FODMAP diet (FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols — poorly digested carbohydrates that can cause gas, bloating, and diarrhea) can also help ease symptoms.

A low-FODMAP diet involves eating fewer foods containing lactose (found in dairy); fruits such as apples, pears, and cherries; cruciferous vegetables like broccoli and cauliflower; beans; and sugar-free gums and mints.

According to the ACG, the low-FODMAP diet should only be followed for a limited period of time. If you opt to try the low-FODMAP diet, it’s important to do so with supervision from your doctor or a registered dietitian trained in gastrointestinal disorders.

According to the ACG, peppermint oil can be used for IBS symptom relief.

Peppermint oil contains L-menthol — a component that can help reduce painful spasms in the gastrointestinal tract. Some research has shown that enteric-coated peppermint oil capsules taken orally can safely and effectively relieve abdominal pain and overall IBS symptoms.

There is limited evidence on the use of probiotics for IBS symptom relief, and the ACG suggests against using them for symptom relief.

Learn More About Treatment for IBS: Medication, Alternative and Complementary Therapies, and More

Prevention of Irritable Bowel Syndrome

You can't prevent IBS, but certain lifestyle modifications can help reduce the frequency and severity of symptoms.

Dietary changes are often key when it comes to stopping IBS symptoms before they start. Depending on the type of IBS you have, you might want to talk to your doctor about limiting or avoiding foods that produce gas (carbonated beverages, wheat, fruits, and vegetables), foods containing gluten, and FODMAPs.

RELATED: Finding the Best IBS Diet: What to Eat and What to Avoid

Learning to handle stress better may also aid in IBS prevention. Counseling, meditation, and yoga are stress-relieving techniques and activities that may help.

RELATED: Mindfulness Meditation Reduces IBS Symptoms and Anxiety, Study Finds

Complications of Irritable Bowel Syndrome

The chronic constipation or diarrhea of IBS can lead to hemorrhoids.

Life with IBS can be complicated and challenging enough on its own. While IBS doesn't permanently damage the digestive tract, it can take an emotional and psychological toll, especially when it comes to your sex life. Symptoms can strike at any moment, causing you to fear an embarrassing incident and easily killing the mood.

Consider some of these suggestions:

  • Talk with your partner about your anxieties.
  • Learn stress-management techniques to help you relax.
  • Avoid trigger foods on the days when you plan to get intimate.
  • Take medications to help relieve pain, gas, and diarrhea so you have one less thing to worry about.

Research and Statistics: Who Has Irritable Bowel Syndrome?

An estimated 25 to 45 million Americans have IBS, and women are about twice as likely to have IBS as men.

Research into IBS is ongoing — we still don't know what causes it, and even diagnosing it can be difficult, because symptoms overlap with other conditions and there's no definitive test. But Barry Marshall, MD, an Australian physician who won the Nobel Prize for discovering the link between stomach ulcers and the bacteria Helicobacter pylori, has devised a way to diagnose IBS by listening to the sounds of the digestive tract. In the Noisy Guts Project, Marshall and his research team are testing an acoustic belt that listens to and records what’s going on in the gut. The recordings are then fed into an artificial intelligence engine that compares the sounds of an IBS gut with a healthy gut.

Related Conditions and Possible Causes of IBS

For years, experts thought that mood disorders such as anxiety and depression contributed to worsening IBS systems. But recent research into the brain-gut connection (mentioned above) suggests the association also goes the other way — that an irritated gut may send messages to the central nervous system resulting in mood changes.

Stress — the body's response to physical and emotional change, pressure, and challenges — is another condition connected to IBS. Stress activates certain neurotransmitters in the brain, which stimulate pain signals in the gut, worsening IBS.

Research suggests that the chronic pain disorder fibromyalgia may also be connected to IBS.

Inflammatory bowel disease (IBD) is a condition that has some overlapping symptoms with IBS, but they are completely different disorders. For one thing, IBS is more common than IBD, affecting about 25 to 45 million Americans, while IBD affects about 3 million American adults.

IBD, usually categorized as either Crohn’s disease or ulcerative colitis, is linked to an abnormal reaction by the body’s immune system. The lining of the intestines becomes inflamed and ulcerated, which causes permanent damage to the digestive tract over time. These conditions often require medication and may even lead to hospitalization and surgery.

Resources We Love

About IBS, from the International Foundation for Functional Gastrointestinal Disorders (IFFGD)

The IFFGD, a nonprofit organization, works with patients, families, healthcare providers, and researchers to increase awareness and understanding of gastrointestinal issues and to improve digestive health. Their page Living with IBS delves into the challenges that people with IBS may face, from traveling to navigating holidays to being pregnant.

IBS Patient Support Group

This online community is great for IBS patients looking for support and connection. Community forums directly address a range of IBS issues, and you can also find resources on living with IBS, including patient diaries, and a podcast that includes conversations with patients, researchers, GI doctors, and dietitians.

Mayo Clinic

For clear, accurate health information, the Mayo Clinic is one of Everyday Health's trusted go-to sources. Their comprehensive coverage of IBS goes beyond the basics, with tips on how to prepare for an appointment to discuss IBS with a gastroenterologist and what questions to ask.

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

In addition to in-depth review of symptoms, treatment, and how to manage IBS, the NIDDK's site also offers the latest on clinical trials potentially available to IBS patients.

Additional reporting by Christina Vogt.

Editorial Sources and Fact-Checking

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