Irritable bowel syndrome (IBS) refers to a group of symptoms that affect your digestive system. It often includes abdominal pain, diarrhea, constipation, and bloating.

Diverticulitis falls into a group of diseases called diverticular disease. It’s characterized by inflammation of bulging pouches in your digestive tract called diverticula.

Some studies suggest that IBS is more common among people with diverticular disease, but the connection still is not clear.

Keep reading to learn more about the similarities and differences between IBS and diverticulitis and how they may be linked.

Common symptomsconstipation
abdominal pain
• constipation
• abdominal pain
nausea and vomiting
• diarrhea (less common)
Causesnot completely knowninflammation of pouches in your intestines called diverticula
Prevalenceaffects about 10 to 15 percent of people• affects about 15 percent of people over age 60 who have diverticulosis (the presence of pouches)
• about 200,000 people hospitalized with diverticulitis each year in the United States
Sex differences1.5 to 2 times more common in women than men• under age 50, more common in men
• over age 50, more common in women
Most common agemost commonly onsets in people younger than 50• more common in older adults
• average age of hospital admission is 63 years old

IBS is a common gastrointestinal disease. It’s characterized by abdominal pain and changes in the frequency and quality of your bowel movements. Symptoms tend to flare up periodically.

How IBS develops still is not well understood. But it’s been linked to:

  • food passing through your gut too quickly or slowly
  • an oversensitivity of the nerves in your gut
  • stress
  • family history (genetics)

Diverticulitis is a condition that develops in your large intestine (also called your colon). It’s caused by an infection in a diverticulum, which is a weakened area of your colon wall that can bulge out and form a pocket or pouch. Diverticula can range from pea-size to much larger pockets.

Diverticulitis develops when one of these pockets becomes inflamed and infected by bacteria in stool that gets pushed into the diverticula. You may feel pain in your abdomen and may also feel nauseous and feverish.

People with diverticulitis in Western societies, such as the United States or Europe, are much more likely to develop diverticula on their left side. But people of Asian descent are more likely to develop diverticula on their right side.

Some people have both IBS and diverticulitis, and misdiagnosis of the two conditions is common. A 2020 study found that about 1 in 5 initial cases of diverticulitis diagnosed without imaging were misdiagnosed.

Some studies suggest that some people with diverticular disease are more likely to develop IBS. But more research is needed to fully understand the link.

A 2014 study found that diverticular disease on the left side or both sides was associated with a higher risk of IBS in a Japanese population. Right-sided diverticular disease was not associated with this risk.

A 2020 study evaluated the association between IBS and diverticulitis. The researchers found that diverticulitis was 3.95 times more common in people with IBS than people without IBS. They also found that IBS was associated with a higher recurrence of diverticulitis.

Both diverticulitis and IBS can cause abdominal pain or discomfort. IBS pain usually relieves after a bowel movement, while diverticulitis pain is constant.

Diverticulitis most often causes pain in the lower left area of the abdomen. People of Asian descent are more likely to develop pain in their right side.

People with diverticulitis tend to be over 40 years old. Most cases of IBS develop before the age of 50.

Symptoms shared by both conditions include:

  • abdominal pain
  • constipation
  • bloating

Symptoms more likely with IBS include:

Symptoms more likely with diverticulitis include:

  • fever and chills
  • nausea and vomiting
  • abdominal tenderness
  • pain coming on suddenly
  • pain not easing after a bowel movement

The exact cause of IBS still is not known. It’s thought that an overly sensitive colon or immune system may contribute to this condition. Some evidence suggests that IBS is more common in people with diverticulitis.

Diverticulitis is caused by pouches in your large intestine that become inflamed and infected. These pouches can become inflamed or infected when bacteria or stool gets trapped in them.

Risk factors for diverticulitis include:

  • a diet low in fiber and high in red meat
  • physical inactivity
  • obesity
  • smoking
  • a change in the balance of microbes (good bacteria) in your digestive tract
  • the use of steroids and nonsteroidal anti-inflammatory drugs (NSAIDs)
  • genetic factors

A doctor can diagnose IBS by:

  • reviewing your symptoms
  • performing a physical exam
  • reviewing your medical and family history

To diagnose diverticulitis, a doctor will likely:

  • check your abdomen for tenderness
  • review your medical history
  • ask you about your symptoms and medications

To help confirm their diagnosis, a doctor may perform additional tests, such as:

IBS does not have a cure. Lifestyle changes, such as avoiding certain foods and following home remedies, may offer some relief. Medications can also help manage symptoms.

Mild diverticulitis can often be treated at home with rest and by avoiding foods that make symptoms worse. A doctor may prescribe antibiotics. Serious cases may require hospitalization or surgery.

You may be able to relieve your IBS symptoms by:

  • eating no more than 3 portions of fresh fruit per day
  • drinking no more than 3 cups of tea or coffee per day
  • following a low FODMAP diet
  • eating your food slowly
  • limiting or avoiding spicy, processed, or fatty foods
  • limiting or avoiding fizzy drinks
  • taking probiotics
  • cooking most of your meals at home using fresh ingredients

You may be able to ease diverticulitis symptoms by:

  • following a liquid diet until pain subsides
  • adding more high fiber foods to your diet
  • avoiding foods that seem to trigger your symptoms

Incorporating the following habits into your daily life may help prevent or reduce symptoms of IBS and diverticulitis:

  • Keep a journal of your symptoms and the foods you eat. This may help you pinpoint the foods that are triggering your symptoms.
  • Try to get regular exercise. Regular, moderate exercise can help boost your overall health and well-being as well as decrease the severity of IBS symptoms.
  • Stay well-hydrated by drinking water or other sugar-free beverages throughout the day. Avoid drinks that are flavored with artificial sweeteners, as these are known to worsen gas and diarrhea if you have IBS.
  • Limit or avoid tobacco, caffeine, and alcohol.
  • Try to incorporate relaxation techniques into your daily life, like breathing exercises, yoga, or meditation.
  • Reduce the nonessential use of NSAIDs.

IBS and diverticulitis are both gastrointestinal conditions that can cause symptoms such as abdominal discomfort and changes to your bowel movements. But they are not the same condition and have different causes.

How or why IBS develops is not well understood. On the other hand, diverticulitis is caused by the inflammation of pouches that can develop within weakened parts of the large intestine. This can be a serious condition that requires hospitalization if the symptoms become severe.

If you think you may have one of these conditions, contact a doctor to get a proper diagnosis. Once the condition has been accurately diagnosed, you can work with your doctor to build a treatment plan that’s right for you.