What You Need To Know About Irritable Bowel Syndrome (IBS)

Types of IBS

What is irritable bowel syndrome?

Irritable bowel syndrome (IBS) is a painful and chronic gastrointestinal disorder of the large intestine usually characterized by abdominal pain and bowel movement issues. This disorder can be confusing due to uncertainty about its cause, its wide range of symptoms, and an often complicated treatment regime.

IBS refers to a group of intestinal symptoms that can vary in duration and severity. Sometimes referred to as spastic colitis/colon, irritable colon, or mucous colitis, IBS tends to be diagnosed after symptoms have persisted over three months.

The symptoms of IBS can vary from person to person, but typically they include:

  • Bloating

  • Pain in the abdomen

  • Excessive gas

  • Diarrhea

  • Constipation

  • Cramping

  • Mucus in the stool

Around 10 to 15% of people in the U.S. have IBS, and women are twice as likely to have IBS than men. 

IBS shouldn’t be confused with IBD or inflammatory bowel disease. IBD is a more serious disorder caused by inflammation of the bowel, which includes ulcerative colitis and Crohn’s disease.

While the medical experts are not really sure what causes IBS, they do know that it is essentially a problem with bowel function.

The different types of IBS

There are three types of IBS, and your doctor can diagnose which category applies to you.

1. Constipation-predominant (IBS-C)

IBS-C is one of the most common types of IBS. You have abdominal discomfort and more than a quarter of your stools are hard/lumpy, while less than a quarter are loose/watery.

If you have IBS-C, you will often have to strain to pass gas and will experience fewer bowel movements than normal.

2. Diarrhea-predominant (IBS-D)

On the other hand, if you have IBS-D, you have abdominal discomfort but tend to have no trouble passing stools. You frequently have to go to the bathroom.

To be diagnosed with IBS-D, more than a quarter of your stools must be loose/watery, and less than a quarter must be hard/lumpy.

Learn more about IBS-D causes, symptoms, and treatment.

3. Mixed (IBS-M, sometimes called IBS-A for alternating)

IBS-M, or IBS-A as it is sometimes called, is diagnosed when you experience bowel movements that are alternatively hard and loose. To be diagnosed with IBS-M, more than a quarter of your stools must be both hard/lumpy and loose/watery. 

The type of IBS that you have will determine the treatment you receive, so it’s important to give your doctor all the information they need to make an accurate diagnosis.

Other forms of IBS can occur in response to other illnesses. These include the following:

1. Post-infectious IBS (PI-IBS)

This type of IBS occurs after an infection in the gastrointestinal system. While the reason PI-IBS develops is not fully understood, it’s thought that infection in the GI system can lead to inflammation in the intestines. The inflammation changes the intestines’ delicate gut flora balance, leading to the development of IBS symptoms.

Diarrhea is common with PI-IBS, and while many people do recover from it, some cases can take years to treat.

2. Post-diverticulitis IBS (PDV-IBS)

Post-diverticulitis IBS occurs after a bout of diverticulitis, an illness where bulging pouches along the lower part of your large intestines become infected or inflamed. It can result in abdominal pain, constipation, and nausea. 

After developing diverticulitis, you can then develop post-diverticulitis IBS, a condition that includes symptoms like diarrhea and vomiting.

Other related conditions


Here are some interesting statistics about irritable bowel syndrome.

Roughly 10 to 25% of U.S. adults experience IBS¹ and 60-65% of them are women². Of all women diagnosed with IBS, 47 to 55% receive a hysterectomy or ovarian surgery, often unnecessarily².

Among IBS patients, 40% will experience mild symptoms, 35% will experience moderate symptoms, and 25% will experience severe symptoms². Roughly only 30% of people with IBS symptoms will reach out to a doctor¹.

Age plays a big factor in IBS development; individuals over the age of 50 are 25% less likely to be diagnosed with IBS, and 50% of IBS patients report having had their first symptoms before age 35¹.

IBS costs around $21 billion annually in medical costs and loss of productivity². 

Worldwide, South Asia has the lowest rate of IBS geographically, with only 7% of people experiencing IBS¹.

  1. The Epidemiology of Irritable Bowel Syndrome (2014)

  2. Statistics | International Foundation for Functional Gastrointestinal Disorders


The most common symptoms that people with IBS experience are:

  • Abdominal pain, specifically in relation to bowel movement

  • Diarrhea, constipation, or alternating episodes of these two

  • Urgency to have a bowel movement

IBS can have variable symptoms and not all patients will experience the exact same ones. Other symptoms that IBS patients might experience include:

  • A bloated stomach

  • The feeling that you haven’t finished a bowel movement

  • Changes in stool appearance

  • Excess gas

  • Whitish-colored mucus in stool

  • More intense symptoms during menstruation¹

The type of IBS that you have will determine the symptoms that you will experience.

1. IBS-C

If you have IBS-C, you are more likely to experience constipation, gas, bloating, and abdominal pain. You will also need to strain during bowel movements.

2. IBS-D

If you have IBS-D, you tend to experience symptoms including diarrhea, abdominal pain, frequent urge to go to the bathroom, and excessive gas.

3. IBS-M

With IBS-M, it can be a bit of the worst of both worlds. Because IBS-M features symptoms of both IBS-C and IBS-D, you will experience a combination of constipation and diarrhea, as well as other common symptoms like abdominal pain and gas.

4. Post-infectious IBS

The symptoms of post-infectious IBS can vary a lot. One study found that 54% of patients with post-infectious IBS developed IBS-M, 38% developed IBS-D, and 6% developed IBS-C. 

Post-infectious IBS can also lead to significant side effects; the same study found that 18% of patients with PI-IBS reported severe symptoms².

5. Post-diverticulitis IBS

IBS symptoms experienced by patients with post-diverticulitis IBS include lower abdominal pain and altered bowel habits¹.


IBS often goes undiagnosed; an estimated 75% of people with IBS won’t talk to their doctor about their symptoms. The most likely reason is they don’t feel the need to get checked out by a doctor, especially when they are only experiencing mild IBS symptoms³.

Diagnosing IBS can be tricky because there is no definitive imaging or blood test to tell you whether you have it. Instead, your doctor will review your symptoms and history and then work to eliminate other similar conditions that do have diagnostic tests, like celiac disease. 

To determine if you have IBS, your physician will look at specific diagnostic criteria:

  • Abdominal pain occurring at least once a week throughout the previous three months

  • At least two of the following:

  1. Pain and discomfort while defecating

  2. Altered frequency of defecation

  3. Altered stool consistency⁴

Based on the assessment, including tests to rule out other diseases, your doctor should be able to confirm whether you have IBS and what type it is.

Before diagnosis

If you haven’t been diagnosed with IBS but suspect that you might have it based on your symptoms, it’s best to set up an appointment with your doctor. 

After explaining your symptoms, your doctor will take a thorough medical history and then work through diagnostic options to eliminate other conditions. If your doctor does diagnose IBS, they will set you up with a treatment plan.

After diagnosis

Once you have been diagnosed with IBS, a good rule of thumb is to let your doctor know about any symptoms that are new or more severe than you would typically experience. 

Specifically, though, you should contact your doctor or specialist if you experience:

  • Severe and persistent abdominal pain

  • Foul-smelling or painful gas

  • Severe and debilitating cramping

  • Excessive diarrhea or constipation that continues for an extended period of time

  • Blood or mucus in your stool

  • Nighttime symptoms that wake you up⁵

Learn more about how IBS is diagnosed here.

  1. Symptoms and Causes of Irritable Bowel Syndrome | National Institute of Diabetes and Digestive Kidney Disease

  2. Characteristics and Risk Factors of Post-Infection Irritable Bowel Syndrome After Campylobacter Enteritis (2021)

  3. Irritable Bowel Syndrome | American College of Gastroenterology

  4. Irritable Bowel Syndrome: Diagnosis and Treatment | Mayo Clinic

  5. Changes You Should Not Ignore If You Have IBS | International Foundation for Functional Gastrointestinal Disorders


IBS is a tricky condition, largely because its exact cause isn’t known. Medical professionals, however, know of certain factors that may play a role in the development of IBS. Here are some of them.


Exposure to stressful events seems to increase IBS symptoms, especially if the exposure occurred in childhood.

Strong muscle contractions in the intestine

It’s thought that abnormally strong or long muscle contractions in the intestine could be responsible for the symptoms of IBS, like gas build-up, bloating, and diarrhea.

Weak muscle contractions in the intestine

On the other hand, weak muscle contractions in the intestine can slow food down, which might be responsible for constipation and hard stools seen with some IBS cases.

Nervous system

There is a strong relationship between your brain and your gut, known as the gut-brain axis. Disrupted brain signals could contribute to IBS symptoms and lead to side effects like abdominal pain and changes to bowel movements.

Gut flora

The microbes that make up the gut flora play an important role in keeping the gut healthy. Disruptions to the gut flora could, therefore, contribute to the development of IBS.


Infection can result in a type of IBS known as post-infectious IBS. An infection can lead to inflammation and disrupt the microbes of the gut.


Diverticulitis is a condition that inflames and/or infects the pouches of the lower part of the large intestine. This inflammation and infection can lead to the development of a type of IBS known as post-diverticulitis IBS¹.

What are the triggers for IBS?

Stress can be a huge trigger for IBS patients, leading to more severe symptoms. It’s thought that this stress connection might be due to the gut-brain axis¹.

Many IBS patients also find that certain foods and drinks can trigger IBS symptoms. Here are some foods to try to avoid if you have IBS.


Foods high in milk sugar, lactose, have been reported to trigger IBS and increase symptoms like diarrhea.


Gluten-free diets have been found to improve IBS symptoms².

Processed foods

Processed foods like sugar, fried foods, high-sodium foods, and sugar-free sweetener have been found to increase IBS risk and could trigger a flare³.


Alcohol can be a big trigger for IBS, thanks to its high sugar and gluten content.

Whole grains and vegetables

Whole grains and vegetables are usually recommended as part of a healthy diet. For patients with IBS, however, the insoluble fiber contained in these products can affect digestion and possibly trigger a flare.

High-FODMAP foods

FODMAP refers to a certain type of carbohydrate, and any food that is high in this carbohydrate can disrupt food adsorption and possibly contribute to IBS symptoms.

High FODMAP foods include onion, garlic, mushrooms, certain fruits, cow’s milk, wheat, cashews, and high-fructose corn syrup⁴ ⁵.

What are the risk factors for IBS?

Certain factors can place you at a higher risk of developing IBS. You’re more likely to have irritable bowel syndrome if you:

Are young. IBS is more common in people aged under 50.

Are a woman. women are twice as likely to have IBS as men.

Have family members with IBS. IBS is thought to possibly have a genetic component.

Have mental health issues. Mental health disorders like anxiety and depression or exposure to stressful situations are thought to contribute toward IBS development¹.


IBS is a long-term condition and unfortunately, there is no magic cure-all. Treatments for IBS focus on reducing the severity of symptoms so that you comfortably live your life.

IBS treatment options typically fall into two categories:

  1. Diet/lifestyle changes

  2. Medication

Diet and lifestyle changes

Diet and lifestyle changes are important components of IBS management since certain foods and events can trigger IBS flares. Your doctor might ask you to reduce your consumption or exposure to:

  • Gluten

  • High-FODMAP foods

  • Alcohol

  • High stress-environments

In addition to asking you to eliminate certain things from your routine, your doctor might also ask you to add in extra foods, supplements, or activities into your life, such as:

  • Drinking more water

  • High soluble fiber foods

  • Healthy sleep habits

  • Low-FODMAP foods

  • Exercise

  • Fiber supplements


While there is no cure-all for IBS, there are medications that you can take to help ease the symptoms. Medicines that your doctor might prescribe include:

Laxatives/anti-diarrheal medications

Depending on your symptoms, your doctor might prescribe you medication to relieve constipation or stop diarrhea.


This medication relaxes the colon and is prescribed in special cases to women with IBS who struggle to manage their severe, chronic diarrhea. It is only approved for restricted and short-term use, as it was associated with a number of serious side effects.


Lubiprostone is another example of IBS medication specifically prescribed for women. This medication increases small intestine fluid secretion to help women with severe and difficult-to-treat IBS constipation to pass stools.

Pain medication

IBS can lead to pain, especially in the lower abdomen. Your doctor might prescribe pain medication like pregabalin or gabapentin to help you manage the pain.


Antibiotic medication like rifaximin can be prescribed to patients with IBS to help reduce bacterial imbalance/overgrowth that can occur with diarrhea.

Anticholinergic medications

Anticholinergic medications work by blocking acetylcholine, a neurotransmitter that can cause muscle spasms in the gastrointestinal tract. In doing so, anticholinergic medications can help stop the painful stomach spasms that often accompany IBS.


Interestingly, antidepressants are often prescribed to patients with IBS. Depression and IBS are closely linked, and antidepressant medication has been found to reduce pain and constipation for patients with IBS¹.

Find more information on relieving IBS pain here.


IBS can be a painful and difficult-to-treat condition. While you can’t prevent getting it, you can remove triggers from your environment that increase the likelihood of IBS symptom flares. By avoiding things that make your IBS worse, you may be able to prevent certain symptoms from occurring and manage the pain and discomfort of IBS better.

Which foods should you avoid if you have IBS?

  • High FODMAP vegetables, e.g., mushrooms, garlic, onion, asparagus, cauliflower, green peas

  • High FODMAP fruits, e.g., apples, peaches, dried fruit, watermelon, mango

  • Dairy, specifically cow’s milk; plant-based milk, and hard dairy cheeses should be tolerable though

  • Gluten, e.g., wheat, rye, barley

  • Legumes and beans

  • Alcohol

  • Caffeine¹

Other behaviors to avoid if you have IBS


Stress can be hard to avoid, but it’s especially important to try and minimize stress in your life if you have IBS. It has been found to exacerbate IBS symptoms.

Relaxation techniques like meditation, yoga, or breathing exercises can help you manage stress.

Not taking medicines as prescribed

If you have IBS, you must follow your treatment regimen as prescribed. Some IBS medications require time to build up in your system, so don’t wait until you have symptoms to take them.


Smoking is bad for everyone, but it can make life especially hard for patients with IBS. Smoking can make IBS symptoms worse, so you definitely want to avoid it².

Doctors & specialists

IBS can be a complicated condition to diagnose and manage, so you might need different types of doctors and specialists during your IBS journey.

The following specialists can be involved in the treatment and diagnosis of IBS:

General practitioner

Your family doctor or GP is the first medical professional you will consult regarding your symptoms. They play an important role in helping you get diagnosed with IBS.


Gastroenterologists are doctors who specialize in disorders of the stomach and intestine. This is the specialist that you will most likely come across if you have IBS.


Depression is common in patients with IBS, so you may be referred to a psychiatrist to help you manage your mental health symptoms.


To reach a diagnosis of IBS, you often have to rule out other disorders like endocrine issues. You might be referred to an endocrinologist for testing to determine whether you have an endocrine disorder that has symptoms similar to IBS.


You may also be referred to an oncologist to rule out carcinoma as the cause of your IBS symptoms.

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