Bacteria is going through a human's digestive system
A bacterial infection such as food poisoning or a virus is often the cause of "stomach bug" symptoms, which is medically known as post-infectious IBS.

Understanding What Post-Infectious IBS Is

If you’ve ever had a "stomach bug," you likely remember how it felt. Fever, diarrhea, vomiting. It’s not a pretty picture, and in some cases, the symptoms linger beyond just a few days, even weeks, months.

A bacterial infection such as food poisoning or a virus is often the cause this condition, which is medically known as post-infectious irritable bowel syndrome (IBS).

However, in some cases, the effects linger for weeks or months — even after a person is no longer vomiting or having severe symptoms. They just can’t get back on track, and the condition develops into post-infectious IBS, or IBS-PI.

What Is IBS-PI?


Post-infectious IBS is a condition that can follow any number of infections that occur in the stomach and intestines. Very often these are caused by a bacterial infection such as food poisoning.

The type of bacteria involved, its toxicity, and the severity of symptoms will affect the risk of developing IBS-PI. Taking antibiotics seems to heighten the risk of developing IBS-PI. Studies show that nearly 10 percent of people with IBS started with IBS-PI. Most often, they develop the diarrhea-dominant form of IBS.

Who Is at Greatest Risk for IBS-PI?

Studies show a pattern of factors that can increase the risk that IBS-PI will develop following a GI infection:

  • Severe initial infection. Generally, post-infectious IBS develops as a result of a serious bacterial infection like food poisoning, instead of a virus
  • Gender. Women are at higher risk than males.
  • Smoking. People who smoke are more likely to develop this condition.
  • Emotional difficulties. People experiencing stress, anxiety, or depression during the three months before the infection are at higher risk for developing IBS-PI.
  • Activity Level. Staying active in the midst of initial GI symptoms increases the risk of developing IBS-PI, according to one study.

However, two factors might protect you from IBS-PI. Those over age 60 have a lower risk. Vomiting during the initial illness may also reduce the risk of IBS-PI by up to 50 percent.

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Why Does the Intestine React This Way?

Scientists believe that during a GI infection, the body experiences an increase in inflammatory cells in the lining of the intestines.

While these cells typically decrease with time, their numbers take longer to diminish in people who develop IBS-PI. This causes a longer inflammatory response in the intestine. The higher numbers of these cells continue to live in the intestine long after the infection began.

What Is the Treatment for IBS-PI?

Doctors treat IBS-PI just as they do IBS, by focusing on relief of symptoms. To ease diarrhea, doctors advise taking Imodium and probiotics supplements. Probiotics help repopulate the small intestine with healthy flora.

Dietary changes can help relieve symptoms of post-infectious IBS. However, what works for one person might not work for another. Some people need to stop eating dairy while others must limit the wheat products they eat.

A special diet called the low-FODMAP diet has helped many people with IBS symptoms. This diet involves eliminating sugars that are difficult to digest. You may need to avoid fruits such as apples, pears, cherries, and apricots. But you can safely eat bananas, cantaloupe, and grapes.

Work with your doctor to find the best dietary pattern that works for you.


For most people, IBS-PI does not become a lifelong illness.

If you have post-infectious IBS, you have a better chance of recovery than people who don’t know the cause of their IBS. Studies show that nearly 50 percent of IBS-PI patients recover and resume normal digestion.

Some people may take years for IBS-PI symptoms to disappear. If they are anxious or depressed, recovery can take longer. Therefore, it’s important to get treatment for emotional difficulties in terms of your overall health.