Antibiotic-associated colitis is when your colon (a part of your large intestine) is inflamed. It is often caused by bacteria growing in your intestine. This growth may happen if you use antibiotics. You may have diarrhea (often bloody) and cramping. The infection is often very serious.

Normal Anatomy of the Intestines

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This condition is caused by harmful bacteria (often the bacterium, Clostridium difficile) growing in your intestines.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. The following risk factors increase your chance of having this condition. If you have any of these risk factors, tell your doctor:

  • You use antibiotics
  • You are elderly
  • You are or have been hospitalized
  • You have a severe illness

Other possible risk factors include:


If you experience any of these symptoms, do not assume it is due to antibiotic-associated colitis. These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your doctor.


Your doctor will ask about your symptoms and medical history, and perform a physical exam. Tests may include:

  • Stool samples—to identify the toxins made by the bacteria
  • Colonoscopy—a thin, lighted tube inserted through the rectum and into the colon to examine the lining of the colon


If you are diagnosed with this condition, follow your doctor's instructions.

Talk with your doctor about the best treatment plan for you. Treatment options include the following:

Fluid Replacement

The first step is to stop taking the antibiotic and replace lost fluids. Talk with your doctor first before stopping the antibiotic. The colitis usually goes away within two weeks of stopping the antibiotic.


You may be given cholestyramine, other antibiotics, and probiotics.

Try not to use antidiarrheal drugs (eg, loperamide and opiates).


In very rare cases you may need surgery. A surgeon may connect your small intestine to an opening in your abdomen. This will divert stool from your large intestine and rectum. This surgery is called an ileostomy. Or the surgeon could remove your large intestine. This is called a colectomy.


The best way to prevent this condition is to reduce using antibiotics. Antibiotics should only be used when your doctor has confirmed that you have a bacterial infection.