What is Irritable Bowel Syndrome?

Irritable bowel syndrome, or IBS, is a functional problem with your gut that causes abdominal pain and changes in your bowel movements, such as diarrhea, constipation, or alternating episodes of both.1 Other symptoms that may be caused by IBS include cramps, bloating, and flatulence.2 Although the proportion of people with IBS varies by country,3 it is probably more common than you realize: an estimated 4% of the population worldwide has IBS. 8

What are the different types of IBS?

While IBS can present in a variety of ways, four types of IBS have been defined based on the different patterns of changes in your bowel movements or abnormal bowel movements:

  • IBS with constipation
  • IBS with diarrhea
  • IBS with mixed bowel habits
  • IBS unclassified9

Your doctor may make treatment decisions based on the type of IBS you have, as some medicines work only for some types of IBS or may make other types worse. Your doctor could diagnose IBS even if your bowel movement pattern does not fit one particular type.4 Risk factors include being young or female; a family history of IBS; and mental health problems. 4 For more information on risk factors, see How does irritable bowel syndrome affect your life?

What can trigger IBS symptoms?

Different theories exist regarding what causes IBS, but the exact cause has not yet been established. Symptoms are known to be triggered or made worse by certain factors:

  • Food. While the role of food allergies or intolerance in IBS is not fully understood, IBS is rarely caused by a true food allergy. However, many people have worse IBS symptoms when they eat or drink certain foods or beverages. These include wheat, dairy products, citrus fruits, beans, cabbage, milk, carbonated drinks, 5 alcohol, caffeine, and spicy or fatty foods.10
  • Stress. While stress and anxiety do not cause IBS symptoms, most people with IBS experience worse or more frequent symptoms during periods of increased stress.
  • Hormones. Women are twice as likely to have IBS, which suggests that hormonal changes play a role. Many women find that their signs and symptoms are worse during or around their menstrual periods.5

IBS fast facts and figures

If you are experiencing symptoms and think you may have IBS, talking to your doctor is the first step in getting diagnosed and finding the right treatment to relieve your symptoms. You may already have questions about IBS and concerns about what an IBS diagnosis could mean. These fast facts should help:

  • IBS is a long-term condition that can come and go over time. 7
  • Women are twice as likely as men to develop IBS.4
  • IBS is unpredictable. Symptoms vary and diarrhea can alternate with constipation.
  • Long-term symptoms can disrupt personal and professional activities and limit individual potential.
  • Approximately 20 to 40% of all visits to gastroenterologists are due to IBS symptoms.
  • IBS is not a risk factor for cancer or colitis. 7
  • IBS does not cause malnutrition. 7
  • IBS does not lead to other health problems or damage your digestive tract.1

Remember, IBS can only be diagnosed by a medical professional. Treatments are available to help manage IBS symptoms, but not all treatments work for all people.6

The first and most important step is to book an appointment with your doctor. They alone are capable of making an accurate diagnosis based on your health profile!

You may want to learn more about IBS, such as how IBS affects your body and how your doctor would make the diagnosis. Read on to find the answers to these questions and more.


  1. National Institute of Diabetes and Digestive and Kidney Diseases, Symptoms & Causes of Irritable Bowel Syndrome. Available at: https://www.niddk.nih.gov/health-information/digestive-diseases/irritable-bowel-syndrome/symptoms-causes (accessed 22.09.2020).
  2. National Health Service, Symptoms: Irritable Bowel Syndrome (IBS). Available at: https://www.nhs.uk/conditions/irritable-bowel-syndrome-ibs/symptoms/ (accessed 22.09.2020).
  3. Ballou S and Keefer L. The Impact of Irritable Bowel Syndrome on Daily Functioning: Characterizing and Understanding Daily Consequences of IBS. Neurogastroenterol Moil. 2017;29(4): doi:10.1111/nmo.12982.
  4. National Institute of Diabetes and Digestive and Kidney Diseases, Definition & Facts for Irritable Bowel Syndrome. Available at: https://www.niddk.nih.gov/health-information/digestive-diseases/irritable-bowel-syndrome/definition-facts#types (accessed 22.09.2020).
  5. Mayo Clinic, Irritable Bowel Syndrome. Available at: https://www.mayoclinic.org/diseases-conditions/irritable-bowel-syndrome/symptoms-causes/syc-20360016#:~:text=Irritable%20bowel%20syndrome%20(IBS)%20is,need%20to%20manage%20long%20term (accessed 22.09.2020).
  6. International Foundation for Gastrointestinal Disorders, Facts About IBS. Available at: https://www.aboutibs.org/facts-about-ibs.html (accessed 22.09.2020).
  7. International Foundation for Gastrointestinal Disorders, IBS Treatment Options. Available at: https://www.aboutibs.org/treatment-main.html (accessed 25.09.2020).
  8. Sperber AD, Bangdiwala SI, Drossman DA, Ghoshal UC, Simren M, Tack J, Whitehead WE, Dumitrascu DL, Fang X, Fukudo S, Kellow J. Worldwide prevalence and burden of functional gastrointestinal disorders, results of Rome Foundation global study. Gastroenterology. 2020 Apr 12.
  9. Schmulson MJ, Drossman DA. What is new in Rome IV. Journal of neurogastroenterology and motility. 2017 Apr;23(2):151.
  10. National Health Service, Diet, lifestyle and medicines: Irritable Bowel Syndrome (IBS). Available at: https://www.nhs.uk/conditions/irritable-bowel-syndrome-ibs/symptoms/ (accessed 28.10.2020).