What is Irritable Bowel Syndrome (IBS)?

What is Irritable Bowel Syndrome (IBS)?

Irritable bowel syndrome (IBS) is a common condition that affects the large intestine (bowel). People with IBS usually have abdominal gas, bloating, and cramps. IBS can also cause diarrhea or constipation, or both. These uncomfortable symptoms can interfere with a person’s quality of life. But IBS does not damage the intestine or lead to more serious conditions – and there are effective treatments for IBS. Other names for IBS include spastic colon and nervous colon.

Types of IBS


Symptoms vary for people with IBS; doctors diagnose IBS types according to symptoms. Different types of IBS are named for how they affect bowel habits.

  • IBS with diarrhea (IBS-D). Most stools are loose and watery.
  • IBS with constipation (IBS-C). Most stools are hard and lumpy.
  • IBS with mixed bowel habits (IBS-M). Hard stools and watery stools occur chronically.
  • IBS undefined subtype (IBS-U). Symptoms vary and do not meet the criteria for other types.

Signs & Symptoms of IBS


The most common symptom of IBS is a change in bowel movement patterns, often accompanied by abdominal pain or discomfort that may be relieved by having a bowel movement. IBS affects people of all ages, including children. However, it is more common in women than in men, and in people in their 20s through age 50. Of the IBS types, IBS-C (with constipation) is more common in women than men. At NewYork-Presbyterian, digestive disease specialists can provide treatments to help manage IBS symptoms.

IBS symptoms vary from person to person, may worsen or improve day-to-day, and can range from mild to severe. Symptoms during an IBS flare-up may include:

  • Constipation (hard stools)
  • Diarrhea (watery stools)
  • Going back and forth between constipation and diarrhea
  • Abdominal pain or cramps
  • Bloating
  • Gas
  • White-colored mucus in the stool
  • Sensation that a bowel movement is not finished
  • For women, symptoms may flare up during menstruation (period)

What Causes IBS?


Experts are uncertain about what causes IBS. The cause may differ from person to person. IBS is diagnosed by its symptoms, as there are no apparent abnormalities in the digestive tract. People with IBS may notice that certain foods, medications, or emotional stressors trigger IBS symptoms. Some possible causes of IBS include:

  • Problems with how the muscles of the intestines contract and move food through them (dysmotility)
  • Nerves lining the intestines are unusually sensitive so that a person with IBS feels pain more intensely (visceral hypersensitivity)
  • Problems in communication between the brain and the digestive tract (brain-gut dysfunction)
  • Abnormal changes in the microbiome

Risk Factors

Risk Factors

IBS is the most common condition that digestive disease experts diagnose. Risk factors for developing IBS may include:

  • Being female: In the United States, IBS affects about twice as many women as men.
  • Age: IBS is more likely to affect people between their 20s and 40s
  • Other people in the family have IBS
  • Certain types of diets
  • Emotional stress, anxiety
  • Severe infections like food poisoning or stomach flu
  • Difficult life events, including in childhood, such as abuse



Moderate to severe IBS can disrupt many aspects of a person’s life. Symptoms can vary and be unpredictable; a person may feel the need to always be near a restroom. Complications that may arise from IBS include:

  • Poor quality of life when symptoms interfere with work, school, social, and personal activities
  • Constant constipation
  • Constant diarrhea
  • Hemorrhoids from long-term constipation and diarrhea
  • Depression
  • Anxiety
Get Care

Trust NewYork-Presbyterian for IBS Care

Seek treatment for your symptoms of IBS at NewYork-Presbyterian. Our caring primary care doctors and digestive disease experts can help you develop dietary and lifestyle changes, as well as find medications, to manage the symptoms of IBS. With treatment, you can get relief from IBS symptoms.