Irritable bowel syndrome (IBS) is a group of digestive symptoms that can cause persistent discomfort. People can often reduce the symptoms with diet and lifestyle changes.

IBS is a chronic condition that typically causes constipation, diarrhea, or a combination of both. People may also experience bloating and cramping.

Many factors may influence the development IBS, from infections to psychological trauma.

This article discusses the symptoms, causes, and treatments for IBS.

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.

IBS is a condition that affects the function of the digestive tract but with no visible damage or signs of disease in the intestines.

The condition is a result of a change or disturbance in bowel function, which then leads to symptoms such as abdominal pain and changes in bowel movements. These symptoms may come and go, or they may be persistent.

The signs and symptoms of IBS can vary from person to person and may include:

  • diarrhea
  • constipation
  • bloating
  • abdominal pain and cramping, which may reduce after passing a stool
  • a feeling that the bowels are not empty after having a bowel movement
  • passing mucus from the rectum

The same symptoms can affect adults and children.

Symptoms in males vs. females

IBS symptoms can be similar between the sexes, but a 2018 review of past research found that females are significantly more likely to have IBS-C and males more likely to have IBS-D. The reasons for this are not yet clear.

A 2022 review also notes that past research has found that men tend to experience more intense pain from IBS than women.

Learn more about IBS in females and in males.

Red flag symptoms

IBS can have similar symptoms to more serious conditions. If a person has any of the following, they should seek medical advice as soon as they can:

  • stool that is black or contains blood
  • unexplained weight loss
  • swelling or pain in one specific area of the abdomen
  • swelling around the rectum
  • abdominal pain at night
  • progressively worsening symptoms

Generally, people with IBS have symptoms that fall into one of three categories:

  • IBS with constipation (IBS-C): This form of IBS mainly causes constipation. A person may have hard, lumpy stools or have difficulty passing them.
  • IBS with diarrhea (IBS-D): This type of IBS mainly causes diarrhea. A person may experience an urgent need to go to the toilet, frequent bowel movements, or watery or loose stools.
  • IBS alternating (IBS-A) or mixed (IBS-M): In these types, a person experiences both constipation and diarrhea.

Scientists are still learning about what leads some people to develop IBS, but there are a few factors that may raise the risk.

Infection

Research suggests a link between IBS and food poisoning and other gut infections. A 2017 study of over 20,000 people found that 10% who experienced an intestinal infection later developed IBS. For those who had protozoa or parasite infections, the rate was 41.9%.

Some microbes may have an impact on the immune system that leads to long-term changes in the gut.

Dysbiosis

Dysbiosis is the medical term for an imbalanced gut microbiome. The microbiome is an ecosystem of bacteria and other organisms that live in the intestines, which influence how humans digest and absorb nutrients. Disturbances to this ecosystem, including the use of antibiotics or infections, may play a role in IBS.

Stress or trauma

The gut and brain are connected, meaning a problem with one can affect the other. This is known as the gut-brain axis. Researchers are still learning how it works, but there is evidence that severe stress may affect gut health.

For example, a 2019 review of past studies, mostly involving veterans, found that people living with posttraumatic stress disorder (PTSD) are more likely to develop IBS.

Motility problems

Gut motility refers to the speed at which the intestines push food through the digestive tract. If motility is too fast or too slow, it may result in IBS symptoms.

Conditions affecting the nervous system, structural differences in anatomy, and some medications are examples of things that may affect motility.

Visceral hypersensitivity

The viscera, or intestines, contain nerves that convey pain signals to the brain. If these nerves become hypersensitive, a person may perceive pain that they otherwise would not.

A flare or flare-up refers to a period when a person’s IBS symptoms worsen. Several factors can trigger IBS symptoms.

For many, diet plays a role in triggering IBS flare-ups. However, it is important to note that this does not mean food is the cause of the IBS itself, nor that dietary changes will cure it. There are many reasons why certain foods may trigger symptoms.

For example, some people may have difficulty with FODMAPs, or “fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.” These are a type of carbohydrate that can be more difficult to digest or that microbes in the gut may ferment, leading to bloating and other symptoms.

Some examples of high FODMAP foods include:

Others with IBS may react to foods that irritate the gut because they are spicy or oily, or because they contain too much or too little fiber.

No two people with IBS are the same. Even among people who do react to FODMAPs, not everyone will react to every FODMAP type.

Caffeine or alcohol

Some find that caffeine can be an IBS trigger, meaning they react to foods such as:

  • tea
  • coffee
  • chocolate
  • energy drinks

For others, alcohol is an IBS trigger.

Stress

Some people find that experiencing stress or anxiety triggers or worsens their IBS.

This does not mean the condition is purely psychological, but for some, addressing mental health does improve symptoms.

Diagnosing IBS is often a process of elimination. First, doctors will ask about a person’s symptoms and may physically examine the abdomen. They may also ask a person to keep a diary to track symptoms over time as well as food intake.

If the symptoms point to a digestive condition, a doctor will try to rule out other conditions that produce symptoms similar to IBS, such as:

If tests for other conditions are negative, they may make the diagnosis of IBS.

In recent years, researchers have developed a specific blood test to diagnose IBS-D, which may speed up diagnosis. However, this test is not widely available yet and does not work for IBS-C.

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

Dietary management

Many people with IBS find that making dietary changes helps reduce their symptoms. What this involves will vary depending on the individual.

For those who have reactions to high FODMAP foods, the MONASH University FODMAP app can help people understand which foods, and which portion sizes of those foods, are less likely to cause problems.

A doctor or dietitian may suggest trying the low FODMAP diet for several weeks before slowly reintroducing moderate or high FODMAP foods.

Additional dietary steps that may also help include:

  • eating regular meals
  • eating slowly and stopping when full
  • limiting caffeinated beverages to no more than 2 cups per day
  • reducing the intake of alcohol or carbonated drinks
  • drinking at least 8 cups of water per day

Keep in mind that a person may need to try different things to find a sustainable diet that works for them. A dietitian can help with this process and give advice on avoiding nutritional deficiencies.

Psychological therapies

Some people may find psychological therapies useful in reducing IBS flare-ups or in managing the impact of symptoms. It may help to try:

Learn more about stress and IBS.

Exercise

IBS symptoms can make it difficult to exercise, but research suggests it has several potential benefits.

A 2024 review of research found that exercise increased the diversity and abundance of “good” gut bacteria in people with IBS.

The authors also highlight that in past studies, people have reported less pain and other symptoms after taking part in an exercise program, and that exercise can also help reduce stress.

Learn more about the best types of exercise for IBS.

Medications

Medications can help manage the symptoms of IBS. Depending on a person’s symptoms, a doctor may suggest:

  • Antispasmodic medications: These reduce abdominal cramping and pain by relaxing the muscles in the gut.
  • Bulk-forming laxatives: Laxatives can help relieve constipation. However, people should take them with caution.
  • Antimotility medications: These can reduce diarrhea symptoms by slowing motility. An example is loperamide, which slows down contractions of the intestinal muscles.
  • Prokinetics: These medications speed up motility to improve constipation.
  • Certain antidepressants: Although antidepressants are for depression, they can sometimes help reduce abdominal pain and cramping, too.

Additional medications a doctor may recommend if other interventions have not helped include:

  • alosetron (Lotronex) for severe IBS-D in females
  • lubiprostone (Amitiza) for IBS-C
  • eluxadoline (Viberzi) for diarrhea and abdominal pain in IBS-D

IBS has similarities to some other conditions. For instance, some people may confuse IBS with IBD.

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.

While IBS does not cause visible damage to the gastrointestinal tract, IBD does. It also causes bowel movements and pain. However, IBD is more likely than IBS to cause:

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

Other conditions that can cause symptoms similar to IBS include:

Below are some commonly asked questions about IBS.

Is IBS curable?

With support and treatment, people with IBS can have a good outlook. However, it is often a long-term condition. Some may find the symptoms change over time.

What are the worst foods for IBS?

There is no single list of worst foods that all people with IBS must avoid. This is because the condition is very individual. Some people may react to certain foods, while others have different triggers.

What is an IBS flare-up like?

Flare-up symptoms will vary depending on the type and severity of the IBS. People with IBS-D may experience sudden cramping, bowel urgency, and diarrhea. People with IBS-C may experience more severe or prolonged constipation and bloating.

Can a person get IBS from eating gluten?

It is unclear if gluten plays a role in causing or worsening IBS. This is because gluten occurs in grains that also contain other potential IBS triggers, such as FODMAPs.

A 2022 randomized controlled trial of 49 people found that most people who followed a low FODMAP diet and also consumed gluten powder did not have worse symptoms than those who followed a low FODMAP diet without gluten.

This suggests that gluten alone may not be a significant IBS trigger. That said, five people in the study did report reactions to the gluten powder, suggesting that some people with IBS may also have gluten sensitivity.

Is IBS contagious?

People can sometimes develop IBS following an infectious illness, such as gastroenteritis. However, IBS itself is not contagious.

IBS is a group of symptoms that do not cause visible damage to the gastrointestinal tract but can be uncomfortable and disruptive to a person’s life.

Scientists are still trying to understand how IBS develops, but an imbalanced microbiome, antibiotic use, gut infections, and psychological stress may be important risk factors. These things may change how the gut functions, resulting in symptoms.

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