Inflammatory bowel disease and irritable bowel syndrome can both cause abdominal discomfort and diarrhea. Inflammatory bowel disease is the term for a group of inflammatory conditions that affect the digestive tract, which include Crohn’s disease and ulcerative colitis.

While the symptoms of inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) can be similar, these conditions have different causes and treatments.

In this article, we look at the symptoms, diagnosis, and treatment of IBD and IBS, as well as the outlook for people with these conditions.

What is IBD?

Man holding his stomach in pain to represent IBd, Crohns, or IBS
IBD can cause irregular or painful bowel movements.

IBD causes inflammation of the gastrointestinal tract, which begins at the mouth and extends through the stomach and intestines to the anus. IBD is a long-term condition with no cure.

The two main types of IBD are ulcerative colitis and Crohn’s disease.

Crohn’s disease can affect any part of the gastrointestinal, or GI, tract. However, this type of IBD most commonly affects the small intestine and the start of the colon. Crohn’s disease can cause patches of inflammation that damage multiple layers of the GI tract wall.

Ulcerative colitis causes inflammation of the colon and the rectum. Unlike Crohn’s disease, it causes continuous areas of inflammation that only affect the innermost layer of the colon wall.

According to a 2014 review, Crohn’s disease is typically more severe than ulcerative colitis but is much less common.

Doctors do not fully understand what causes IBD, but they believe that it occurs due to a problem with the immune system. Genetics seem to play a role too as IBD can run in families. Certain lifestyle factors, such as smoking, can also increase the risk of developing IBD.

IBD symptoms

Common symptoms of IBD can include:

  • diarrhea
  • bloody stools and rectal bleeding
  • sudden urges to have a bowel movement
  • abdominal pain and cramping
  • a sense of the bowels not being empty after a bowel movement
  • unintended weight loss

Other symptoms may include:

The symptoms can vary considerably from person to person depending on the location and severity of the inflammation. They also tend to come and go in cycles, so people experience flare-ups, when their symptoms suddenly get worse, and periods of remission, during which they have no or few symptoms.

IBD diagnosis

To diagnose IBD, a doctor will typically start by taking a medical history and performing a physical exam. They may also order one or more of the following tests to aid their diagnosis:

  • X-ray or CT scan. These create an image of the inside of the body and allow a doctor to check for signs of any problems.
  • Endoscopy. This procedure involves inserting an endoscope, which is a thin tube with a light and camera on it, down a person’s throat into their GI tract to look for signs of IBD.
  • Colonoscopy. This test requires the insertion of an endoscope up through a person’s anus into their rectum and colon.
  • Blood tests. A healthcare professional can analyze a small sample of a person’s blood to look for signs of inflammation and rule out other conditions.
  • Stool tests. These require the individual to provide a sample of their stool for analysis. Doctors use stool tests to rule out other conditions.

IBD treatment

Doctor in office holding different pill bottles discussing prescription medication with patient
A doctor will prescribe medication based on the severity of the IBD.

There is no cure for IBD, so the aim is to keep a person in remission. Doctors use treatment to relieve the symptoms that a person is experiencing, prevent flare-ups, and maintain periods of remission. The treatment that they choose will depend on the severity of the symptoms.

Many different medications are available for IBD:

  • Aminosalicylates, which help reduce inflammation. Doctors often prescribe these drugs to people with mild symptoms.
  • Immunomodulators, which can treat mild-to-moderate IBD and include steroids and azathioprine among other medications. Immunomodulators work by suppressing immune-system activity and reducing inflammation.
  • Biologics. Doctors tend to prescribe these drugs when other treatments have not worked. Biologics target specific parts of the immune system to reduce inflammation.

Some people may need surgery to remove or bypass damaged parts of their GI. However, according to the Centers for Disease Control and Prevention (CDC), surgery for IBD is becoming less common due to advancements in medications.

IBD outlook

IBD is a lifelong condition for which there is currently no cure. Symptoms tend to come and go in cycles. At times, a person may find that their symptoms suddenly flare-up and get worse. They may then enter a period of remission during which their symptoms improve.

Treatment for IBD typically focuses on relieving a person’s symptoms and trying to induce and maintain remission.

What is IBS?

IBS is a long-term condition that affects the intestines and causes a group of digestive symptoms that tend to occur together. Unlike IBD, IBS does not cause any visible signs of damage or inflammation in the GI tract.

IBS is a common condition. According to the National Institute of Diabetes and Digestive and Kidney Diseases, IBS affects around 12 percent of people in the United States. It is more common in women than in men, and it is more likely to develop in people under the age of 50 years than in older people.

It is not clear exactly what causes IBS, but doctors think that digestive problems and increased gut sensitivity may play a role. Stressful life events and mental health issues, such as depression and anxiety, may also increase a person’s risk of developing IBS. It is possible that the condition runs in families too.

IBS symptoms

As with IBD, the symptoms of IBS tend to come and go in cycles. Flare-ups often last for several days, and symptoms may be worse after eating. Some females with IBS may experience more symptoms during their period.

IBS usually involves sudden changes in bowel habits, such as diarrhea or constipation. The symptoms can vary from mild to severe and may include:

  • abdominal pain and cramping
  • gas and bloating
  • a sensation of incomplete bowel evacuation
  • mucus in the stool

IBS Diagnosis

A blood test may help a doctor diagnose IBS.
A blood test may help a doctor diagnose IBS.

To diagnose IBS, a doctor will typically review a person’s symptoms and medical history. They are likely to ask about the type and frequency of bowel movements and the appearance of stools. The doctor will also perform a physical exam.

There are no specific tests for IBS. However, to rule out other conditions, a doctor may order:

IBS Treatment

Treatment for IBS typically involves making dietary and lifestyle changes. A doctor may recommend:

  • eating more fiber
  • avoiding foods that contain gluten
  • following a specific IBS-friendly diet
  • exercising regularly
  • reducing and managing stress
  • getting adequate sleep

A doctor may also recommend or prescribe medications to treat specific symptoms of IBS. These may include:

  • anti-diarrheal drugs, such as loperamide (Imodium)
  • laxatives or fiber supplements for constipation
  • antispasmodics to help reduce abdominal pain and cramping
  • antidepressants, which can also help treat abdominal pain and cramping

IBS outlook

There is currently no cure for IBS, and a person may find that their IBS gets better or worse over time. It is usually possible to manage IBS by making lifestyle and dietary changes. Keeping a symptoms diary to identify and avoid triggers, such as stressors or certain foods, can also help reduce flare-ups.

A doctor can also prescribe medications to relieve specific symptoms and provide tailored dietary advice to help minimize discomfort.


IBD and IBS are both long-term conditions that can cause similar symptoms, such as abdominal pain and changes in bowel habits. The symptoms of both IBD and IBS tend to come and go, alternating between flare-ups and periods of remission. However, these two conditions have different causes and treatments.

IBD, which includes Crohn’s disease and ulcerative colitis, is an autoimmune condition that causes inflammation of the GI tract, whereas IBS seems to result from digestive problems and increased gut sensitivity. Medications can reduce gut inflammation in people with IBD, while the treatment of IBS focuses primarily on lifestyle and dietary changes.

Although there is no cure for either IBS or IBD, researchers are finding new and more effective ways to manage symptoms and prevent flare-ups of both conditions.