Diverticulitis vs. IBS

Irritable bowel syndrome (IBS) and diverticulitis are both diseases that affect your digestive system. Because they have some overlapping symptoms, it may be difficult to know if they are caused by diverticulitis or IBS.

IBS refers to a group of symptoms that affect your digestive system, including abdominal pain, diarrhea, constipation, and bloating. Diverticulitis is an inflammation of diverticula (little "outpouchings") in the wall of the colon.

Doctor and patient going over medical history
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It is possible to have both IBS and diverticulitis.

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

What Is Diverticulitis?

Diverticulitis is a condition in which diverticula—small pouches (sacs) that can form in the lining of the large intestine—become inflamed or infected. These pouches are most likely to be found in the sigmoid colon, which is the lowest part of the large intestine.

Diverticulitis is commonly confused with diverticulosis. Diverticulosis refers only to the presence of these pouches in the colon, with no inflammation or infection involved. Diverticular bleeding is when the diverticula start to bleed.

What is IBS?

IBS is a group of intestinal symptoms that typically occur together. The symptoms vary in severity and duration from person to person.

When diagnosing IBS, healthcare professionals look for symptoms that have been present for at least six months and have occurred at least three days per month for the last three months. IBS is not the same as inflammatory bowel disease (IBD).

Symptoms of Diverticulitis vs. IBS

Symptoms that can occur in both diverticulitis and IBS include:

  • Abdominal pain
  • Bloating
  • Constipation
  • Vomiting

Symptoms that are characteristic of diverticulitis include:

  • Lower abdominal pain and tenderness, particularly on the left side
  • Abrupt change in bowel movements, such as constipation or diarrhea
  • Cramping
  • Fever and chills
  • Pain not relieved by a bowel movement

Symptoms more common with IBS include:

  • Vomiting
  • Diarrhea
  • White mucus in bowel movements
  • Relief of pain after a bowel movement

For many people, diverticulosis alone causes no symptoms and is only diagnosed incidentally during another imaging test of the colon. In others, the presence of these sacs may contribute to constipation, diarrhea, abdominal pain, and bloating, which are symptoms of IBS as well.

Causes of Diverticulitis vs. IBS

A definite cause has not been established for either IBS or diverticulitis. It is thought that genes may play a role as well as environmental factors.

Obesity, smoking, lack of exercise, and dietary habits (such as eating a lot of red meat and not getting enough fiber) may contribute to diverticulitis.

IBS is thought to involve a "brain-gut connection." Stress, depression, and anxiety often accompany the disease.

A 2020 study found that participants with IBS were almost four times as likely as those without it to have diverticulitis.

Other researchers have concluded that a link may exist, but that the connection and its implications for treatment are not yet clear.


Increasing your fiber intake is recommended for both IBS and diverticular disease. You can do this by eating high-fiber foods or taking a fiber supplement.

There are also certain lifestyle changes that can prevent diverticulitis flare-ups. Although these factors are not necessarily associated with IBS, making these changes will help to improve your overall and digestive health:

  • If you are a smoker, take steps to stop.
  • Be sure to exercise regularly.
  • Maintain a healthy weight.
  • Keep alcohol use to a minimum.
  • Keep your use of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) to a minimum.

People with IBS may also find it helpful to:

  • Keep a diary of foods, symptoms, and bowel habits to see if patterns emerge.
  • Limit intake of gas-forming foods like beans and cruciferous vegetables (e.g.,broccoli, cauliflower and cabbage).
  • Follow a low-FODMAP diet.
  • Limit or eliminate intake of milk or dairy to see if it helps IBS symptoms. Lactose intolerance (the natural sugar in milk) is a common food intolerance.

Before making any major changes to your diet, it is best to talk to your healthcare provider for advice.


IBS and diverticulosis are both diseases that affect the digestive tract. The two conditions have some overlapping symptoms, so it can sometimes be tricky to know which one you might have. Furthermore, it is possible to have both conditions. Certain dietary and lifestyle measures can be helpful for both conditions.

10 Sources
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By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.