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What is Inflammatory Bowel Disease? What Patients Need to Know

Commentary09/18/26 Aaron E. Walfish, MD, Mount Sinai Medical Center

Many conditions can cause stomach pain and related symptoms. For patients and their doctors, effective treatment starts with identifying what’s causing those symptoms. When patients experience prolonged diarrhea and abdominal pain, one condition doctors will consider is inflammatory bowel disease (IBD). In IBD, different parts of the digestive tract become inflamed, often causing recurring abdominal pain and diarrhea. If untreated, that inflammation can lead to serious complications. Early diagnosis and treatment are important. Here’s what patients need to know about IBD.

IBD is different from IBS

IBD is sometimes confused with irritable bowel syndrome (IBS). The two have similar acronyms and some similar symptoms, but they are fundamentally different conditions. IBS is a functional disorder, meaning the digestive tract can appear normal but does not function properly. Common symptoms of IBS include abdominal pain, bloating, constipation, diarrhea, and changes in bowel habits. Doctors typically diagnose IBS based on these symptoms.

IBD, on the other hand, involves chronic inflammation that can be detected during a colonoscopy or through imaging and confirmed during biopsies. Untreated IBD can cause permanent damage and complications, including fistulas, which are abnormal tunnels forming between parts of the digestive tract, other organs, or the skin, and abscesses, which are pus-filled cavities, undernutrition, and an increased risk of colorectal cancer. Because IBD is a systemic inflammatory disease, it can cause inflammation and symptoms in other parts of the body. Patients may experience joint pain or joint inflammation, eye inflammation, skin conditions, and fatigue.

Crohn disease and ulcerative colitis are the two primary types of IBD

Most people with IBD have either Crohn disease or ulcerative colitis. Crohn disease is an inflammatory bowel disease in which chronic inflammation typically involves the lower part of the small intestine, the large intestine, or both; however, inflammation may affect any part of the digestive tract. Ulcerative colitis is a chronic inflammatory bowel disease in which the large intestine (colon) becomes inflamed and ulcerated (pitted or eroded), leading to flare-ups (bouts or attacks) of bloody diarrhea, abdominal cramps, and fever.

There is no cure for IBD

Doctors don’t fully understand what causes IBD. Evidence suggests that normal intestinal bacteria inappropriately trigger an immune reaction in people with a genetic predisposition. Several additional risk factors have been identified, including smoking.

While there is no cure for IBD, treatments have advanced considerably in recent decades. Treatment approaches generally focus on controlling inflammation and healing the lining of the digestive tract, both of which can help prevent complications and improve quality of life for patients.

Treatment has become increasingly personalized. Doctors will typically work with patients to help determine the medication that works best for them. In some cases, surgery may be required.

IBD needs to be treated — regardless of symptoms

When IBD is more active, it’s known as a “flare-up,” and patients experience more symptoms. Periods without symptoms are known as remission.

Sometimes, patients with IBD think that if they’re not experiencing symptoms, they are better and don’t need to continue treatment. This is not true. Even when symptoms are not occurring, patients can still have inflammation, leading to further damage and complications. In fact, treatment may be less effective if it is stopped and started again. Adhering to treatment, including medications and regular monitoring and appointments, is essential.

Diet and stress do not cause IBD

Eating certain foods or avoiding others cannot cure IBD. There are no specific dietary recommendations for people with IBD. Clinical trials have not shown that diets are effective. Some patients may find that specific diets do help reduce their IBD symptoms, but effects vary from person to person.

Nutrition does play an important role in symptom management and overall health. People with IBD should eat healthy, balanced meals and stay hydrated, particularly after a flare-up. IBD can cause vitamin deficiencies, so it’s also important for patients to ensure they’re getting enough iron, vitamin B12, vitamin D, calcium, and folate.

Sometimes, patients believe that managing their stress more effectively will make their IBD disappear. That’s not true. Stress can lead to flare-ups and make symptoms worse during a flare-up, but stress does not cause IBD.

Ultimately, managing IBD includes staying current on preventive care, focusing on good sleep, controlling stress, staying active, and building a strong relationship with doctors. Treatment options have improved significantly. Adhering to treatment, even when symptoms improve, is absolutely essential.

To learn more about IBD, visit the Manuals page on the topic.