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Colitis: Causes, Symptoms, & How to Treat

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Written by Adam Pont, MD, PhD.
Gastroenterology Fellow, New York Presbyterian Hospital/Columbia
Last updated October 25, 2022

Colitis quiz

Take a quiz to find out if you have colitis.

Colitis is an inflammation of the lining of the colon. There are a number of causes, including infection and an overactive immune system. Often, you have stomach pain and diarrhea. Getting the right diagnosis is critical to managing your symptoms.

Colitis quiz

Take a quiz to find out if you have colitis.

Take colitis quiz

Is colitis a serious disease?

Pro Tip

Colitis is not one disease with a single cause. It has several different causes. Your experience and treatment will depend on the cause. —Dr. Adam Pont

Colitis is caused by inflammation of the inner lining of the colon (large intestine). Colitis has many different causes.

It could be caused by an infection (from bacteria, parasites, or viruses). You may have overactive immune system activity. This is the case with the inflammatory bowel diseases (IBD)—Ulcerative Colitis and Crohn's Disease—as well as with microscopic colitis. You may have decreased blood flow to the colon (ischemic colitis), or previous bowel surgery (diversion colitis).

Most people with colitis experience abdominal (belly) pain and loose stool (diarrhea). With the right treatment, symptoms usually begin to improve within a week or two, though it depends on the cause of the colitis.

Most common symptoms

While symptoms depend on the form of colitis, you will likely have belly pain, loose stool, and many bowel movements. Bloating is also common.

You may notice blood in your stool. You may also have a fever. It is important to keep track of your symptoms and the order in which they occur. For instance, severe, sudden abdominal pain followed by bloody loose stools is common with ischemic colitis.

Main symptoms

  • Belly pain, cramping, or discomfort
  • More frequent bowel movements with loose stools
  • Fever (more common with infections or IBD)
  • Pain while passing stool (more common with IBD)
  • The feeling of not getting all the stool out during a bowel movement (more common with IBD and some parasites)
  • Bloating
  • Blood in your stool

Other symptoms you may have

  • Fecal incontinence (stool coming out by accident)
  • Feeling lightheaded or dizzy—from dehydration caused by watery stools
  • Weight loss

These symptoms are more likely if you have IBD

  • Eye pain
  • Mouth ulcers
  • Joint pain

Dr. Rx

Ask your doctor: How long until my symptoms begin to improve? What should I do if my symptoms have not improved by that time? Also, how do I prevent this from happening again? —Dr. Pont

What should you do for colitis?

If you have a fever, blood in your stool, or sudden weight loss, along with frequent loose stools, immediately call your doctor (if available) or go to the ER.

If you are experiencing lightheadedness or dizziness, go to the ER or call 911.

Otherwise, make an appointment with your doctor within 2 weeks. They may then refer you to a gastroenterologist (specializes in the digestive tract).

Colitis quiz

Take a quiz to find out if you have colitis.

Take colitis quiz

Colitis causes

Colitis is caused by inflammation of the inner lining of the colon. The inflammation makes it harder for the colon to absorb water, causing loose stool and other symptoms.

There are many potential causes, including:

  • Infection with bacteria (particularly C. difficile), parasites, or viruses
  • Overactive immune response (ulcerative colitis or Crohn's disease; microscopic colitis)
  • Decreased blood flow to the colon from blood clots, narrowed arteries, or extremely low blood pressure (ischemic colitis)
  • Having a stoma or ostomy (surgery where the surgeon created an opening in your abdomen for your stool to collect outside your body). The absence of stool flow in the portion of the bowel beyond the stoma (and less exposure to certain molecules in the stool) can cause colitis.

Pro Tip

Your gut has many billions of bacteria and other microorganisms living in it. This collection is called the “microbiome.” One potential future treatment for some forms of colitis may involve changing your microbiome by introducing new bacteria from a healthy donor—a fecal microbiota transplant. Such transplants are already being used successfully to treat certain types of infectious colitis that do not respond to repeated courses of antibiotics. —Dr. Pont

What is the best treatment for colitis?

Treatment depends on the cause. Infectious colitis is typically diagnosed with a stool sample.

For all other types, you may need to have a colonoscopy to confirm the diagnosis and how severe it is. A colonoscopy uses a long flexible camera to look at the inside of your colon. It is usually done under sedation.


Once you know the cause, your doctor will probably prescribe medication to treat it. If you have bad diarrhea, you may also need to drink lots of fluids and take an over-the-counter anti-diarrheal medicine such as loperamide.

If taking antibiotics, be sure to finish the whole prescription, even if you feel better.

  • Infectious colitis (caused by a virus): no medications are usually necessary.
  • Infectious colitis (caused by a parasite or bacteria): Your doctor will prescribe an antibiotic based on which parasite or bacteria is causing the colitis.
  • Colitis from IBD: Medication will depend on many factors and sometimes your doctor will prescribe a combination of drugs. Options include oral medications and those delivered by enema. They may recommend biologic medications. These have antibodies that neutralize or block molecules in your body that are involved in inflammation. They are given by injection or through an IV.
  • Ischemic colitis: Medicines to reduce blood clots or treat low blood pressure.
  • Microscopic colitis: Your doctor may give you a steroid medication called budesonide for 4 weeks. If symptoms improve, they may reduce the dose. Your doctor may recommend changes to your diet as well.
  • Diversion colitis: You may need a medicated enema (a liquid or foam solution that you insert into your anus).

Medical procedures

  • Colitis caused by IBD: If you have ulcerative colitis and medications don’t help, your doctor may recommend surgery to remove your colon.
  • Ischemic colitis: If severe, you may need surgery to repair the colon or remove portions of it.
  • Diversion colitis: If possible, your doctor may recommend surgery to reverse the stoma or ostomy. The surgery reconnects your bowel so that your stool flows through its entire length. If this is not possible, there are other treatments to try.

Ready to treat your colitis?

We show you only the best treatments for your condition and symptoms—all vetted by our medical team. And when you’re not sure what’s wrong, Buoy can guide you in the right direction.See all treatment options
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Colitis quiz

Take a quiz to find out if you have colitis.

Take colitis quiz

How does a person get colitis?

Risk factors depend on the type of colitis.

Infectious colitis is more common in people with a weakened immune system. Due to cancer or other conditions or medications (like steroids). If you’re already taking antibiotics, that's a risk for colitis caused by C. difficile (a bacteria). Traveling to areas where parasites are common puts you at risk of infectious colitis caused by parasites.

IBD (ulcerative colitis or Crohn’s) is more likely if you have a family history of IBD or other autoimmune diseases. And having IBD also increases your risk of getting infectious colitis.

Heart disease, particularly atrial fibrillation (an irregular heartbeat) or atherosclerosis (plaques in your arteries), is a risk factor for ischemic colitis.

Microscopic colitis can be caused by certain medications (like ibuprofen). And from previous colon infections.

What causes colitis in kids?

One common cause of colitis in infants and children—and rarely in adults—is allergic colitis. It can usually be managed with changes in diet.

Colitis in infants or children can have different symptoms than in adults. Children may vomit, have less of an appetite, or have allergic-type symptoms. Call your pediatrician immediately if your child has recurrent loose bloody stools.

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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Gastroenterology Fellow, New York Presbyterian Hospital/Columbia
Dr. Pont is currently a fellow in Gastroenterology at New York Presbyterian Hospital/Columbia, where he also completed his residency in Internal Medicine. Dr. Pont received his medical degree and PhD at the New York University School of Medicine. He earned his BS in Biological Systems Engineering at the University of Nebraska-Lincoln.

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