What Triggers IBS Symptoms?

Reviewed by: HU Medical Review Board | Last reviewed December 2022

Doctors do not know the exact reasons why a person develops irritable bowel syndrome (IBS). It is likely a combination of many factors, including genetics, changes in gut bacteria, how well food moves through the gastrointestinal (GI) tract (motility), and food sensitivity, among others.1-3

IBS symptoms are different for everyone. What causes these symptoms to worsen also varies from person to person.3

Specific foods

The foods that trigger symptoms in one person may not affect others. However, common trigger foods in people with IBS include:1-5

  • Wheat
  • Corn
  • Dairy products like milk, cheese, and yogurt
  • Fatty foods
  • Beans
  • Caffeine
  • Alcohol
  • Processed foods
  • Vegetables that produce gas, such as broccoli, cauliflower, kale, and cabbage
  • Greens such as chives, leeks, and shallots

Fermentable, poorly absorbed carbohydrates may also cause IBS symptoms or make them worse. These include:1-5

  • Fructose – found in honey, fruit, fruit juices, and high-fructose corn syrup
  • Fructans – found in wheat-based products and onions
  • Sorbitol – found in "sugarless" and diet foods

A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) may improve IBS symptoms. If you are curious about the low-FODMAP diet, talk with a dietitian.1-6


The intestines and brain are connected, so when your mind is stressed, your gut may be too. In times of high stress, anxiety, or other disruption to your environment, it is not uncommon for IBS symptoms to worsen.1,3


Some drugs can alter the gut's microbiome, and not in a good way. For example, antibiotics that are used to treat infections can kill off good bacteria our guts need in order to stay healthy. This can trigger IBS symptoms.1,3


IBS is more common in women than in men. Many women report that symptoms worsen around their menstrual cycle. While the exact relationship is not well understood, hormones may play a role in IBS and its severity.7


Infections caused by viruses, bacteria, or other germs can cause changes in the gut that lead to IBS. For instance, traveler’s diarrhea, which may be a form of food poisoning, has been shown to increase the likelihood of developing IBS.1

These acute GI infections cause inflammation and changes to the gut microflora. After having an acute GI infection, a person is 6 times more likely to develop IBS.1

Improve symptoms by making changes to your diet

Some IBS triggers you cannot control. But some you can, especially when it comes to diet. These tips can help with symptoms:3,6

  • Eat smaller meals.
  • Avoid fatty foods.
  • Eat high-fiber foods.
  • Avoid milk products.
  • Avoid carbohydrates.
  • Limit caffeine and alcohol.
  • Eat lean meats like chicken and avoid fatty meats like beef and pork.
  • Stay hydrated.

Keeping a diary of symptoms and triggers can be helpful in finding out what specific things trigger your IBS symptoms. Consider working with a dietitian to develop a meal plan that is right for you.3,6

Tracking how you navigate or reduce these triggers can also make a difference in preventing and handling symptoms in the future. You know your body best and can make a roadmap for yourself on how to best support it.3,6

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