What is irritable bowel syndrome?

Irritable bowel syndrome (IBS) is a common condition that affects your digestive system, especially the large intestine. It causes uncomfortable symptoms like belly pain, cramping, bloating, gas and changes in bowel habits such as diarrhea, constipation or both.

Although IBS can be disruptive and frustrating, it doesn’t cause damage to your digestive tract or raise your risk of conditions like colon cancer. It is a chronic (long-term) condition, but many people are able to manage it with a combination of lifestyle changes, diet, stress reduction and when needed medication or therapy.

Most people with IBS have mild to moderate symptoms that come and go. A smaller number experience more severe symptoms that may need extra support or treatment. Working closely with your doctor can help you find the right strategies to relieve symptoms and improve your quality of life.

doctor examining a patient for IBS symptoms

Types of IBS

Doctors classify IBS into subtypes based on stool consistency and frequency. Knowing which type you have is important because not all types respond to the same treatments, and treatments that may help with one type can make another type worse. Still, your doctor can diagnose you with IBS even if your symptoms don’t fall into one of these subtypes.

The three subtypes of IBS are:

  • IBS with constipation (IBS-C): More than a quarter of your stools are hard, and less than a quarter are loose or watery
  • IBS with diarrhea (IBS-D): More than a quarter of your stools are loose, and less than a quarter are hard
  • IBS with mixed bowel habits (IBS-M): With this type, you experience both watery and hard stools equally on the days that you have bowel movements.

Irritable bowel syndrome symptoms

The characteristic symptoms of IBS are belly pain and changes in your bowel movements. Sometimes, IBS symptoms happen together all at once or individually. You may also have several days when you don’t experience any symptoms. Flare-ups are also common with IBS—these are times when your symptoms are more severe than usual.

Symptoms can also affect men and women differently. Women, for example, are more likely to have belly pain and constipation, and their symptoms may get worse during their period. Men, on the other hand, often experience diarrhea.

In general, symptoms of IBS include:

  • Belly (abdominal) pain
  • Bloating
  • Constipation
  • Cramps
  • Diarrhea
  • Feeling like you haven’t completely emptied your bowels after pooping
  • Gassiness
  • Stool that contains mucus

When to see a doctor

It’s normal to occasionally experience gastrointestinal discomfort such as gassiness, diarrhea and constipation. But see your doctor if your symptoms are severe and have lasted for at least three months. Your doctor can perform a thorough evaluation and help you find a treatment that offers relief.

What causes IBS?

Experts have not yet identified the causes of IBS, but they believe a combination of factors contributes. Functional GI disorders like IBS are thought to be caused by a communication breakdown between the brain and the gut. These communication problems may speed up or slow down the movement of food through your intestines, leading to diarrhea, constipation and other symptoms. Poor signaling between the brain and your gut can also make nerves more sensitive and cause them to overreact to normal digestion, triggering discomfort and other symptoms.

Other potential causes of IBS include:

  • Changes to your microbiome: Your gut microbiome includes good bacteria and other microbes. People with IBS appear to have different microbiomes than people without IBS.
  • Environmental factors: Stress (particularly early-life stress), food intolerances and antibiotic use have all been linked to IBS symptoms.
  • Infections: IBS symptoms can develop after a severe GI infection called gastroenteritis.

Irritable bowel syndrome risk factors

IBS is very common and can affect people of all ages and races. Anyone can get IBS, but in the US, it affects more women than men and usually appears before age 45. You may be at greater risk based on your lifestyle, history of certain medical conditions and genetics.

Risk factors for IBS include:

  • Being female: About twice as many women experience IBS, possibly due to hormone fluctuations.
  • Having a family member with IBS: It’s not entirely clear how genetics affect IBS, but people with IBS tend to have a family member with the condition.
  • Having a mental health condition: People with IBS are more likely to have anxiety, depression or post-traumatic stress disorder.
  • Previous gastrointestinal infections: Bacterial gastroenteritis and other infections disrupt the gut microbiome and increase the risk of IBS.
  • Stress: Abnormal nerves and hormones associated with stress can trigger irregular intestinal movement.

How is IBS diagnosed?

Generally, doctors diagnose IBS based on your symptoms and medical history. There’s no test that can diagnose the condition. However, your doctor may order tests to rule out other conditions with similar symptoms, like celiac disease, Crohn’s disease, ulcerative colitis, microscopic colitis or infectious colitis.

After other conditions have been ruled out, your doctor may use established diagnostic criteria or symptom types to identify IBS and guide treatment.

  • Rome criteria. These criteria include belly pain and discomfort averaging at least one day a week in the last three months. This also usually occurs with at least two of the following: pain and discomfort related to defecation, a change in the frequency of defecation, or a change in stool consistency.
  • Type of IBS. IBS is often categorized into four types based on your symptoms. This helps guide treatment:
    • IBS with constipation (IBS-C)
    • IBS with diarrhea (IBS-D)
    • Mixed IBS (IBS-M), which includes both constipation and diarrhea
    • Unclassified IBS, for symptoms that don’t clearly fit the other categories

Irritable bowel syndrome treatments

Treatment for IBS involves a personalized approach based on your specific symptoms and IBS type.

Treatment for IBS-D, or IBS with diarrhea, focuses on preventing loose stools and treating any associated dehydration. Treating IBS-C, or IBS with constipation, aims to relieve hard stools. If you have IBS with diarrhea and constipation, your treatment will aim to restore normal bowel function.

IBS treatment often combines different approaches. You may benefit from dietary changes, lifestyle adjustments, therapy or medications that target specific symptoms.

Dietary changes

What you eat can play a big role in triggering or relieving IBS symptoms. Your doctor may recommend limiting or avoiding certain foods like spicy, fatty or highly processed meals. Some vegetables, like cabbage or broccoli, can cause gas and bloating.

Tracking what you eat and how you feel after each meal can help you and your doctor identify potential triggers.

Your doctor may recommend:

  • Avoiding gluten: This protein found in foods like wheat, barley and rye can trigger IBS symptoms. Following a gluten-free diet may help.
  • Eating more fiber: Fiber helps you poop more easily if you have constipation. The type of fiber found in beans, fruits and oats (soluble fiber) seems to be most helpful for people with IBS.
  • Following the low-FODMAP diet: FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. These are sugars found in a variety of foods that can be difficult to digest. Avoiding FODMAP foods may help your symptoms.

Find specialized IBS care

At Baylor Scott & White, we offer several locations for the treatment of irritable bowel syndrome, including gastroenterology centers across North and Central Texas. Our experienced team is ready to provide personalized care to help improve your quality of life. Whether you're seeking diagnostic testing, treatment options or ongoing support, our teams are here to help you.  

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