How IBD is Different From the Stomach Flu

These conditions have similar symptoms but different treatments

Gastroenteritis, often called the stomach flu, is an illness caused most often by a virus. It may also be caused by bacteria or parasites, though this is less common. It causes symptoms that include diarrhea and vomiting.

A stomach bug usually lasts for a few days. However, diarrhea can go on for as long as one to two weeks. Peak times for the stomach flu being spread from person to person are the winter months, when more people are indoors.

The inflammatory bowel diseases (IBD), which includes Crohn's disease, ulcerative colitis, and indeterminate colitis, are chronic, lifelong conditions. IBD also can cause symptoms that are similar to gastroenteritis, such as diarrhea, abdominal pain, and vomiting.

However, these two conditions will be treated differently. For people who have IBD, it may be challenging to know if symptoms are the beginning of the disease flaring up, or if they are from a virus.

Catching a flare-up early is important. People with IBD will want to know the difference between what it feels like to have a disease flare-up versus having a virus that causes diarrhea.

Key Differences Between IBD and the Stomach Flu

Verywell / Ellen Lindner

The Stomach Flu

There are several different types of viruses that can cause what we call the stomach flu. It is a highly contagious condition.

It gets passed from person to person usually through the fecal-oral route. What this means is that a person who has the virus sheds it in their stool. It can get on that person's hands after they use the bathroom. When that person touches something, like a doorknob, the virus can be left on that surface

A person who is uninfected might then pick up the virus on their hands and, in turn, become infected after touching their eyes, nose, or mouth. This is why it is important to wash hands well. The virus can also spread to uninfected people through food and water that is contaminated.

Symptoms of a stomach bug can include:

  • Abdominal pain
  • Chills
  • Decreased appetite
  • Diarrhea
  • Fever
  • Muscle pain
  • Nausea
  • Weight loss
  • Weakness
  • Vomiting

Inflammatory Bowel Disease

IBD is a condition for which there is no cure. Therefore, symptoms will come and go throughout a person's lifetime. Some people with IBD have a clear understanding of when a flare-up is starting. Others don't have any warning and a flare-up may come on more suddenly. Some of the common symptoms of IBD include:

  • Abdominal pain
  • Blood in the stool
  • Diarrhea
  • Fever
  • Weight loss

Differences Between IBD and Stomach Flu

While there are clearly several signs and symptoms that are in common between IBD and the stomach flu, there are differences.

The symptoms of stomach flu often come on quite suddenly, typically over a period of a few hours. It's not usually the same with IBD. The symptoms of IBD are often more subtle and worsen over a period of days or weeks.

There can be complications from the stomach flu, the most chief of which is dehydration. Dehydration is also common in IBD, especially after having surgery on the bowels.

There are complications and extra-intestinal manifestations in IBD that don't occur with the stomach flu. Some of these include skin conditions, eye conditions, and joint pains. Some people who live with IBD notice that these extra-intestinal manifestations start before, or at the same time as, the digestive symptoms.

In most cases, there is no specific treatment for stomach bugs. Rest and fluids are usually all that's needed until the virus has run its course.  A flare-up of IBD, however, will likely not improve without treatment, which can include medication, a change in diet, and/or lifestyle changes.

Tips to Know the Difference

Knowing the difference between an IBD flare-up and a stomach bug might be something that comes to be understood over time. There are some key differences that people with IBD might use to decide what is causing symptoms.

  • Symptoms of an IBD flare-up will last longer than a few days.
  • Symptoms of the stomach flu should start to get better in a few days.
  • Stomach flu does not cause blood in the stool.
  • People may become sick with the stomach flu after a close contact has been ill.

How to Avoid Stomach Bugs

Stomach viruses can be difficult to avoid because they spread so easily and quickly. There are a few things to keep in mind, however, that may help in keeping viruses away:

  • Proper handwashing: Because the stomach flu may be spread when we touch a surface with the virus on it and then touch our face, keeping hands clean is key. Washing hands after using the bathroom, before cooking food, and before eating is important. Using hand sanitizer when washing hands with soap is not possible may also be helpful.
  • Avoid people who are ill: This can be challenging because many bugs can be spread before people are feeling sick. It can help to let friends and family know that it is important to stay away when they feel ill.
  • Disinfect high-touch surfaces: Keeping doorknobs, counters, faucets and other high-touch surfaces disinfected can also help in avoiding viruses. 

Red Flag Symptoms

It's certainly possible to have both gastroenteritis and an IBD flare-up at the same time. That could lead to symptoms that become concerning. For that reason, it's important to keep in mind some symptoms that are a reason to seek medical attention right away. This includes:

A Word From Verywell

It's important that people who live with IBD get vaccinated against common infectious diseases. Unfortunately, there's no vaccine for stomach bugs. For that reason, it's important for people with IBD to be vigilant about viruses.

Having IBD does not make it more likely that people will catch a stomach virus. However, some medications that are used to treat IBD may make people more likely to come down with certain types of infections.

If there is a concern about how to avoid catching viruses or in recovering from them, people with IBD should speak to their physicians. It may also be helpful to know when viruses are starting to spread in the community. That can help people with IBD take more precautions to avoid bugs when the risk is higher.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. MedlinePlus. Gastroenteritis.

  2. MedlinePlus. Viral gastroenteritis.

  3. National Institute of Diabetes and Digestive and Kidney Diseases. Treatment of viral gastroenteritis (“stomach flu”).

  4. Gong SS, Fan YH, Han QQ, Lv B, Xu Y. Nested case-control study on risk factors for opportunistic infections in patients with inflammatory bowel disease. World J Gastroenterol. 2019;25:2240-2250. doi:10.3748/wjg.v25.i18.2240.

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.