Gastroenteritis and colitis are two conditions that involve inflammation of the digestive tract. Gastroenteritis affects the stomach and intestines. Colitis only involves the colon.

Although both conditions can cause abdominal pain and diarrhea, they often have different causes and may require different treatment approaches.

Gastroenteritis is inflammation of the stomach and intestines that typically occurs due to a viral or bacterial infection. Diarrhea ranging from mild to severe is the most common symptom. Other symptoms people typically experience are nausea and vomiting. People can usually recover without treatment, although hydration is important in the healing process.

Most cases of colitis are chronic, and risk factors can include genetics and medications. However, some cases can be acute and occur due to infections, such as Clostridioides difficile (C. difficile).

Keep reading to learn more about the link between gastroenteritis and colitis, including how the symptoms and treatment for both conditions compare.

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Colitis and gastroenteritis share some similarities. For example, both conditions:

However, there are some key differences between the two conditions. These include:

  • The location of inflammation: Gastroenteritis involves the stomach and intestines, whereas colitis only involves the colon.
  • Symptoms: People with gastroenteritis might experience nausea and vomiting, whereas people with colitis may experience bloody diarrhea.
  • Chronicity: Colitis is more of a chronic condition.
  • Causes: In the case of gastroenteritis, an infection may be the cause.
  • Resolution: Gastroenteritis will likely resolve on its own, whereas colitis may require medical attention.

Dehydration is a complication that commonly occurs in people with viral gastroenteritis. This happens when a person loses too much fluid and electrolytes through vomiting and diarrhea.

If someone has colitis, it means there is inflammation in the lining of their colon.

The most common type of colitis is ulcerative colitis, which causes ulcers or sores. The inflammation can extend from the rectum to the inner lining of the colon.

Other types of colitis include:

  • Crohn’s colitis, a type of Crohn’s disease
  • microscopic colitis, which has two types: lymphocytic and collagenous
  • ischemic colitis, which occurs due to reduced blood flow to the colon
  • pseudomembranous colitis, which is often the result of an infection with C. difficile bacteria

Cytomegalovirus, a common strain of the herpes virus, can also cause colitis.

Learn more about colitis, including the different types.

People may refer to gastroenteritis as stomach flu. It is not a type of flu that affects the respiratory system. In a person with gastroenteritis, the lining of the intestines has become inflamed. Viruses, bacteria, or parasites can cause the condition.

Viral gastroenteritis is the second most common illness in the United States. Often a norovirus infection is the cause of this condition. The virus spreads through contaminated food or water or contact with a person who has the infection.

Learn more about bacterial gastroenteritis.

Some symptoms of colitis and gastroenteritis might overlap.


Colitis symptoms vary between the different types and from person to person.

Common symptoms of ulcerative colitis include:

Additionally, an individual may experience an urge to move the bowels even though they are empty or sudden urgency to move the bowels.


Symptoms of viral gastroenteritis may include:

The causes of colitis and gastroenteritis might also overlap. For example, infections can cause both conditions. Other causes can include the following:


Various conditions can cause colitis. These include infection, inflammatory bowel disease, ischemia, radiation, certain drugs, and abnormal reactions of the immune system. Doctors refer to colitis that results from an immune reaction as microscopic colitis. Colitis can also occur in some people who have immune deficiency disorders.

Doctors are not entirely sure of the causes of ulcerative colitis but think it could involve:

  • genetics
  • an altered gut microbiome
  • abnormal immune reactions
  • environmental causes

Other types of colitis may have specific causes. For example, in pseudomembranous colitis, C difficile infection is usually the cause. However, inflammatory conditions, disruption to blood flow, and certain medications can contribute.


Gastroenteritis is an infectious illness that viruses, bacteria, or parasites can cause. Norovirus is usually the cause, but other viruses could be involved, including:

Doctors may recommend specific treatments for people with colitis and gastroenteritis.


Doctors treat colitis according to the cause. For example, ulcerative colitis may require medications to reduce inflammation, such as corticosteroids or immunosuppressants. However, if these medications do not successfully ease symptoms or the individual has complications, a doctor may recommend surgery to remove the colon and rectum.

Likewise, if someone has Crohn’s disease, doctors may prescribe medications to suppress their immune response. They may also recommend dietary changes, and surgery may become necessary if medications cannot control the symptoms.

If an individual has pseudomembranous colitis because of a C. difficile infection, doctors may prescribe antibiotics such as metronidazole, vancomycin, or fidaxomicin.


Treatment of viral gastroenteritis is much more straightforward, and many people recover without medical treatments. However, it is important to replace lost fluids and electrolytes if a person has severe diarrhea.

In some cases, adults may take some over-the-counter medicines to treat diarrhea due to viral gastroenteritis. People should speak with a doctor before taking these medications, especially if they are experiencing bloody diarrhea or fever.

Sometimes it is not possible to prevent a person from developing colitis.

However, people can help prevent infectious forms of colitis and viral gastroenteritis by following basic hygiene practices, including:

  • washing the hands thoroughly with soap and water after using the bathroom or changing diapers and before handling food or visiting a healthcare facility
  • disinfecting bathroom and kitchen surfaces
  • using disposable gloves and washing hands after contact with someone who is ill
  • washing clothing or bedding of an ill person with soap and chlorine bleach

Any individual who develops diarrhea and has dehydration symptoms should seek medical attention immediately, as severe dehydration may require hospital treatment.

People with the following symptoms should also contact a doctor immediately:

  • diarrhea lasting more than 2 days
  • frequent vomiting
  • high fever
  • severe pain in the abdomen or rectum
  • black, tarry stools
  • stools with bright red blood or mucus
  • weakness or excessive fatigue

Older adults, pregnant people, and those with a weakened immune system or other health conditions should also seek their doctor’s advice if they have symptoms of colitis, gastroenteritis, or dehydration.

Gastroenteritis and colitis are two gastrointestinal disorders that can cause abdominal pain, diarrhea, and other symptoms. While these conditions share some similarities, they are not the same.

Gastroenteritis, or stomach flu, is an inflammation of the stomach and intestines that usually results from a viral or bacterial infection. It is typically an acute, short-lived problem. Prevention of gastroenteritis usually involves good hygiene practices.

Colitis refers to a group of conditions that involve inflammation of the colon and are usually chronic. Examples include ulcerative colitis and Crohn’s disease.

If a person experiences severe symptoms of either condition, it is important to contact a doctor right away.