Concurrent bloating and diarrhea are common gastrointestinal (GI) symptoms that can disrupt your life.

If your symptoms only last a few days, they may be simply caused by a food disagreeing with you or a mild illness like food poisoning or a stomach flu. Chronic and severe symptoms might be a sign of a potentially serious condition like inflammatory bowel disease (IBD).

Keep reading to learn more about some of the reasons why you may have bloating and diarrhea at the same time.

Here are some potential causes of diarrhea and bloating.

Eating too much

Eating too much can overload your GI system and can cause symptoms such as bloating or diarrhea.

Almost everybody eats too much from time to time. If it becomes a regular problem, it can be a sign of a binge eating disorder.

One of the defining symptoms of binge eating disorder is having a sense of lack of control during overeating episodes. On average, binge eating occurs at least once a week for a minimum of 3 months.

Too much fiber

Most nutritionists recommend an intake of about 18–38 grams of fiber per day for adults, or about 8–20 grams per 1,000 calories.

Fiber adds bulk to your stool that helps it move through your GI tract and keeps your gut healthy.

Consuming too much fiber can cause bloating or other symptoms like diarrhea or gas. People at risk include:

Learn about how much fiber is too much.

Food intolerance or allergy

A food intolerance is when your body can’t digest a particular food or ingredient. Some intolerances are extremely common. For example, up to 70% of people have some degree of lactose intolerance.

Learn more about the most common food intolerances.

Food allergies are when your immune system overreacts to certain foods — such as dairy, peanuts, or soy — and an abnormal response is triggered. In severe cases, a food allergy can cause anaphylaxis.

Learn more about the most common food allergies.

Both food allergies and intolerances can cause symptoms like bloating or diarrhea.

Irritable bowel syndrome (IBS)

IBS may affect up to 15% of people in the United States. It’s subcategorized into the following based on your symptoms:

Other symptoms may include:

Stomach flu (viral gastroenteritis)

The stomach flu is a stomach infection usually caused by the norovirus. Symptoms often improve within 1–3 days and rarely last more than a week. Besides bloating and diarrhea, you may have:

Food poisoning

Food poisoning rarely lasts longer than a week and is usually treatable with home remedies. It’s caused by ingesting food contaminated with bacteria, viruses, or other small organisms.

Symptoms are similar to those of the stomach flu.

Small intestinal bacteria overgrowth (SIBO)

SIBO is the overgrowth of bacteria in your small intestines. It’s thought to be a common cause of chronic diarrhea. About 80–90% of cases are thought to be caused by:

Medication side effects

Many medications cause bloating or diarrhea as a side effect. For example, antibiotics can destroy healthy bacteria in your gut, which may cause GI symptoms.

Celiac disease

Celiac disease is an autoimmune disease triggered by consuming gluten. Gluten is found in:

  • wheat
  • rye
  • barley


Diverticulitis is inflammation of sacs along your gastrointestinal tract that can cause pain, bloating, diarrhea, and other GI symptoms.

Inflammatory bowel disease (IBD)

IBD is the collective name for Crohn’s disease and ulcerative colitis. It can cause severe inflammation in your gut that may lead to bloating, diarrhea, and other GI symptoms.

Bloating and diarrhea can be caused by many viral infections, including COVID-19. The prevalence of diarrhea among people with COVID-19 has been reported anywhere between 2–49.5%.

Many conditions that cause bloating and diarrhea also cause gas. They include:

  • IBS
  • IBD
  • medication side effects
  • eating too much fiber
  • food intolerances
  • food allergies

Bloating and diarrhea usually aren’t serious, but it’s important to see a doctor if you have:

Doctors may use the following tests to diagnose your condition.

Food intolerance or allergy• eliminating certain foods and slowly adding them back to see if you have a reaction (elimination diet)
• blood test
lactose breath test
IBS• tests to rule out other conditions
Stomach flu• stool tests
Food poisoning• stool tests
• other tests, based on your symptoms
SIBObreath test
endoscopy to take an intestinal fluid sample
Celiac disease• blood tests
Diverticulitis• blood tests
• stool tests
• imaging tests (such as X-ray or CT scan)
IBDendoscopy or colonoscopy
• imaging tests

Treatment options include the following.

Eating too much fiber• lowering fiber intake
Food intolerance or allergy• avoiding triggering foods
lactase pills for lactose intolerance
IBS• medications for symptoms
• avoiding certain foods
• eating smaller meals
SIBO• antibiotics
• nutritional supplements
Stomach flu• getting plenty of rest and fluids
• medications to reduce symptoms
Food poisoning• getting plenty of rest and fluids
• medications to reduce symptoms
Celiac disease• avoiding gluten
Medication side effects• changing medication or dose
• anti-inflammatory medications
• pain medications
IBD• dietary changes
• surgery
• biologics
• corticosteroids
• other medications

Bloating and diarrhea are common and often occur together. Most causes, such as stomach flu or food poisoning, usually aren’t serious.

It’s a good idea to speak with a doctor if your symptoms are severe or interfering with your daily life. They can order tests to help find the underlying cause.