What is IBS?


Irritable bowel syndrome (IBS), a disorder of the gut-brain axis, was previously called a functional gut disorder. IBS is a common digestive disorder that affects 10-15% of the worldwide population and is most commonly diagnosed in females 50 years of age and younger.

Irritable bowel syndrome (IBS) used to be a diagnosis of exclusion but is now considered a diagnosis of inclusion. This means that someone will need to meet specific criteria to receive an irritable bowel syndrome (IBS) diagnosis from a gastroenterologist. Doctors typically use the Rome IV criteria, which include a change in bowel habits and abdominal pain at least once per week for the past three to six months. The change in bowel habits may be related to a change in frequency or consistency of bowel movements (ranging from diarrhea to constipation). 

Healthcare professionals will also use other tests to rule out other conditions. For example, they will recommend blood tests be performed to rule out Celiac Disease (CD) or to test for Inflammatory Bowel Disease (IBD), particularly if you have certain red flag symptoms, like blood in your bowel movements or weight loss.


IBS Symptoms

The symptoms of irritable bowel syndrome (IBS) can vary from person to person. They can also vary in severity. Gastrointestinal symptoms include bloating, gas, abdominal pain, and altered bowel habits. The altered bowel habits may be characterized by a change in stool frequency or form and can fall anywhere from constipation to diarrhea. Other irritable bowel syndrome (IBS) symptoms that people report are bowel movement urgency and abdominal distention or severe bloating with added abdominal girth.

Symptoms help categorize IBS into three main subtypes:

  • IBS-D: Irritable bowel syndrome (IBS) with Diarrhea is characterized by symptoms of bowel movement urgency, loose stools, bloating, and/or abdominal pain and cramping. 
  • IBS-C: Irritable bowel syndrome (IBS) with constipation is characterized by bloating and infrequent and/or hard stools. 
  • IBS-M: Mixed irritable bowel syndrome (IBS). You may experience both IBS-D and IBS-C symptoms, with both diarrhea and constipation. 
  • IBS-U: You meet criteria for IBS, but your bowel movements do not meet any of the above subtypes.



The exact cause of irritable bowel syndrome (IBS) is unknown at this time. However, there are multiple possible causes, including:

  • Altered gut motility: when the gut moves too quickly, resulting in diarrhea, or too slowly, resulting in constipation.
  • Bacteria: an imbalance of gut bacteria or gut dysbiosis.
  • Infection: often called post-infectious irritable bowel syndrome (PI-IBS).
  • Visceral hypersensitivity: an increase in abdominal pain sensations, often brought on by eating.


IBS Treatment

Treatment options have greatly improved over the past decade. Various medications can help manage IBS symptoms, along with diet and non-diet therapies. 


  • Medications vary based on IBS symptoms and the IBS subtype, whether IBS-C, IBS-D, or IBS-M.
  • These include antispasmodics, eluxadoline, lubiprostone, and linaclotide.
  • Certain antidepressants may also be prescribed. 


  • Fiber: Change in fiber intake. The ACG recommends soluble fiber to help with constipation, frequency, and a reduction in bloating.
  • Elimination: The low FODMAP diet is a three-phase elimination diet that requires a restriction of fermentable carbohydrates for a short period, followed by reintroduction. The third phase is a personalization period, where non-triggers are added back into the Irritable Bowel Syndrome Diet. The low FODMAP diet has been shown to work in 3 out of 4 people.
  • Other changes: Certain foods may increase IBS symptoms. These include fatty or spicy foods, caffeine, and/or alcohol. 

Non-diet therapies: 

  • Stress management, including meditation.
  • Gut-directed hypnotherapy: This addresses the miscommunication between the gut-brain axis. Studies have shown that gut-directed hypnotherapy can be just as effective as a low FODMAP diet in treating IBS symptoms. It is particularly beneficial in those whose IBS symptoms are exacerbated by psychological triggers.
  • Cognitive Behavior Therapy (CBT): Studies have shown that CBT can be effective in improving abdominal pain, diarrhea, and constipation.
  • Supplements: fiber, peppermint oil

Irritable bowel syndrome (IBS) is a chronic health condition with no cure. However, it does not cause any long-term damage to your digestive tract. Irritable bowel syndrome (IBS) can impact people emotionally, socially, and physically. A 2019 quality of life study found that people with irritable bowel syndrome (IBS) miss 1.5 days of work or school per month due to their irritable bowel syndrome (IBS). Luckily, there are multiple modes of treatment for IBS that can help manage gastrointestinal symptoms and improve the overall quality of life.