Irritable bowel syndrome (IBS) is a long-term gastrointestinal disorder that can cause persistent discomfort. People can often manage their IBS symptoms with diet and lifestyle changes.

IBS, also called spastic colitis or nervous colon, is a chronic condition with symptoms that change over the years. Symptoms often ease as individuals learn to manage the condition.

IBS is common. As many as 10–15% of people in the United States have it. It affects twice as many females as males. Many factors influence IBS, and research suggests that microbes present during infectious gastroenteritis may trigger a long-term reaction.

This article discusses symptoms, causes, treatment, and how diet can affect IBS.

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IBS is a functional gastrointestinal disorder. These types of disorders generally affect a part of the GI tract with chronic, sporadic, and unpredictable symptoms.

In IBS, there is a change or disturbance in bowel function. This can cause abdominal pain and changes in bowel movements that can include diarrhea, constipation, or both.

IBS causes these symptoms without causing any visible damage to the digestive tract.

Healthcare professionals often refer to IBS with diarrhea as IBS-D and IBS with constipation as IBS-C. If IBS causes both diarrhea and constipation, healthcare professionals may call it IBS-A, which stands for alternating bowel habits, or IBS-M, which stands for mixed bowel habits.

Signs and symptoms of IBS may vary from person to person and often mimic symptoms of other conditions.

The most common symptoms of IBS include:

  • changes in bowel habits
  • abdominal pain and cramping, which often reduce after passing a stool
  • a feeling that the bowels are not empty after passing stools
  • passing mucus from the rectum
  • swelling or bloating of the abdomen

Symptoms in males vs. females

IBS symptoms tend to vary between females and males. Research shows that women experience more constipation and men experience more diarrhea.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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Symptoms in children

Children most commonly experience pain in the abdomen, which often occurs around bowel movements, and changes to their bowel movements such as diarrhea, constipation, or both.

A flare or flare-up refers to periods when a person’s symptoms worsen. Often, a person may experience a flare immediately following a meal, or it can take longer in some people. A person experiencing a flare will have many of the same symptoms associated with IBS, including:

  • abdominal pain
  • changes in stool, such as constipation or diarrhea
  • bloating
  • mucus in stool
  • feeling as though a movement did not completely void the rectum

IBS often presents similarly to other conditions. For instance, people may confuse IBS with inflammatory bowel disease (IBD).

While IBS is a syndrome that does not cause visible damage to the gastrointestinal tract, IBD is a group of diseases that occur when the immune system attacks cells in the intestines. This immune malfunction damages the gastrointestinal tract and causes chronic inflammation.

Crohn’s disease and ulcerative colitis are two of the most common types of IBD. Similar to IBD, these both cause changes in bowel movements and stomach pain. However, a person with IBD, including Crohn’s disease or ulcerative colitis, is more likely than a person with IBS to have the following:

  • bloody stools
  • loss of appetite
  • fever
  • weight loss

People with IBD also have an increased risk of colon cancer.

Other conditions besides IBD that may cause IBS symptoms include:

Several factors can trigger IBS to flare or worsen. The following are some common causes of IBS.

Dietary factors can play a role in triggering IBS symptoms.

Symptoms often worsen after a person consumes certain products. These could include chocolate, milk, or alcohol. They may cause either constipation or diarrhea.

Some fruits, vegetables, and sodas can also trigger bloating and discomfort. It is unclear whether a food allergy or intolerance plays a role.

Common dietary triggers of cramping or bloating include foods that cause flatulence, such as:

Other foods that can trigger flares include:

  • dairy products
  • sugar-free gum
  • some candies
  • products with caffeine in them (though symptoms with these may be due to sugar, sorbitol, or caffeine intolerance rather than IBS)
  • alcohol

2. Microbial imbalance

While the exact causes are unknown, some experts believe that microbial factors may play a key role. The gut contains what is known as the microbiome, which holds an ecosystem of bacteria and other microbial organisms. Experts believe treatments that target the microbiome may help alleviate symptoms in the future.

3. Food poisoning and infection

Research suggests a link between IBS and food poisoning. In fact, 1 in 9 people who experience food poisoning develops IBS at a later date. The microbes involved in infectious gastroenteritis may have an impact on the immune system that leads to long-term changes in the gut.

Infections such as gastroenteritis may trigger post-infectious IBS.

4. Stress

Researchers believe there is a connection between the brain and the gut, which means that when a person experiences stress or anxiety, it may trigger or exacerbate their IBS.

IBS may link to mental health. For example, research shows that people living with post-traumatic stress disorder (PTSD) have a higher risk of developing IBS.

5. Other factors

Several other factors may play a role in causing IBS symptoms to occur. They can include:

  • genetic factors
  • hormones
  • digestive organs with a high sensitivity to pain
  • response to medication
  • an unusual response to infection
  • a malfunction in the muscles that move food through the body
  • an inability of the central nervous system to control the digestive system

Flare triggers

A common trigger of an IBS flare is eating. A person may find that certain foods have a higher chance of causing symptoms to flare or worsen.

It could be helpful for a person to record what they eat and how their symptoms respond. Taking this step could help them reduce flares in the future by avoiding trigger foods.

Other triggers are similar to triggers of IBS as a whole. They include stress, hormones, or taking certain medications.

Treatment options for IBS aim to relieve symptoms and improve a person’s quality of life.

Treating IBS usually involves some dietary and lifestyle changes, as well as learning how to manage stress.

Dietary management

The following steps may help relieve IBS symptoms:

  • avoiding sugar alternatives in some chewing gums, diet foods, and sugar-free sweets, as they can cause diarrhea
  • consuming more oat-based foods to reduce gas or bloating
  • not skipping meals
  • eating at the same time every day
  • eating slowly
  • limiting alcohol intake
  • avoiding carbonated, sugary beverages such as soda
  • limiting the intake of certain fruits and vegetables
  • drinking at least 8 cups of fluid per day, for most people

Avoiding gluten can also reduce the risk of flares. Gluten-free food products and alternatives are now widely available.

Learn more about gluten.

Additional dietary steps that can also help a person reduce the risk of a flare include:

  • only eating until full
  • limiting coffee, tea, or caffeinated beverages to no more than 2 cups per day
  • avoiding known trigger foods

Changes in eating habits can help manage symptoms. However, no IBS diet works for every person. A person may need to go through a process of trial and error to find a consistent, comfortable diet that works for them.

Learn more about foods that people living with IBS should avoid.

Psychological therapy

Some people may find psychological therapy useful in reducing IBS flares and the impact of symptoms. Techniques include:

  • Hypnotherapy: This may help alter how the unconscious mind responds to physical symptoms.
  • Cognitive-behavioral therapy (CBT): This may help people develop strategies for reacting differently to the condition through relaxation techniques and a positive attitude.

Exercise may also help reduce both symptoms of anxiety and the physical symptoms of IBS in some people.


The following medications may help IBS symptoms:

  • Antispasmodic medications: These reduce abdominal cramping and pain by relaxing the muscles in the gut.
  • Bulk-forming laxatives: These can help a person relieve constipation. However, people should take them with caution.
  • Antimotility medications: These can reduce diarrhea symptoms. Options include loperamide, which slows down contractions of the intestinal muscles.
  • Tricyclic antidepressants (TCAs): These often help to reduce abdominal pain and cramping.

Additional medications specific to IBS treatment include:

  • alosetron (Lotronex) for severe diarrhea-predominant IBS in females
  • lubiprostone (Amitiza) for constipation-predominant IBS in females
  • rifaximin (Xifaxan), an antibiotic that can help reduce diarrhea in people with IBS
  • eluxadoline (Viberzi) for diarrhea and abdominal pain in people who have IBS with diarrhea

These are typically the last line of treatment when other lifestyle or therapeutic interventions have not helped, and symptoms remain severe.

Until recently, there was no specific imaging or laboratory test to support an IBS diagnosis. There is now a blood test that can accurately reveal whether a person has IBS with diarrhea or IBD. However, laboratory testing for this is not yet readily available.

As part of the diagnosis, a doctor will aim to rule out conditions that produce symptoms similar to IBS. They will also follow a procedure to categorize the symptoms.

There are three main types of IBS:

  • IBS-C: A person experiences stomach pain, discomfort, bloating, infrequent or delayed bowel movements, or hard or lumpy stools.
  • IBS-D: There is stomach pain, discomfort, an urgent need to go to the toilet, frequent bowel movements, or watery or loose stools.
  • IBS-A or IBS-M: A person experiences both constipation and diarrhea.

Many people experience different types of IBS over time. A doctor can often diagnose IBS by asking about symptoms, for example:

  • Have there been any changes in bowel habits, such as diarrhea or constipation?
  • Is there any pain or discomfort in the abdomen?
  • How often is there a bloated feeling?

A blood test may help rule out other possible conditions, including:

If specific signs or symptoms suggest a different condition, further testing may be necessary. These include:

  • anemia
  • localized swelling in the rectum and abdomen
  • unexplained weight loss
  • abdominal pain at night
  • progressively worsening symptoms
  • significant amounts of blood in the stool
  • family history of IBD, colorectal cancer, or celiac disease

A 2019 review of 38 studies found that the following characteristics and conditions may increase the risk of IBS:

  • having gastroenteritis
  • being younger than approximately 35 years or older than 65 years
  • a history of anxiety or depression
  • stress
  • a family history of IBS
  • pain
  • sleep disorders

Below are some commonly asked questions about IBS.

What are the worst foods for IBS?

According to the National Health Service (NHS) in the UK, a person with IBS should avoid the following foods:

  • foods that are hard to digest (like cabbage, broccoli, cauliflower, brussels sprouts, beans, onions and dried fruit)
  • products containing a sweetener called sorbitol
  • cut down on high-fibre foods like wholegrain foods (such as brown bread and brown rice), nuts and seeds

The above foods are thought to contribute to bloating, cramps, farting, and diarrhea in people with IBS.

Can a person get IBS from eating gluten?

Some people with IBS may have sensitivity to gluten. If a person has concerns that gluten may be contributing to their bowel issues, they should ask their doctor for testing.

Is IBS curable?

It is not possible to cure IBS permanently. However, treatment options, including lifestyle and dietary changes as well as medications, can help a person manage and reduce their symptoms.

Is IBS contagious?

While some research shows that IBS may be related to bacteria in the small intestine, it is not contagious. However, a person may develop post-infectious IBS after an intestinal illness such as gastroenteritis.

IBS is a gastrointestinal syndrome that does not cause damage to the gastrointestinal tract. However, it can cause uncomfortable and disruptive symptoms.

Though it is common, it can be difficult for a doctor to diagnose IBS due to the lack of tests available to diagnose it and the symptoms it shares with many other conditions.

There is no cure for IBS. However, treatments are available that can help a person manage their symptoms and regain a better quality of life.