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Symptoms

  1. Irritable bowel syndrome (IBS) symptoms

Irritable bowel syndrome (IBS) symptoms

Different kinds of IBS are diagnosed according to their symptoms, with people experiencing different combinations of the symptoms of irritable bowel syndrome, including bloating, diarrhea, constipation and painful abdominal cramps.

Diarrhea and constipation may each affect people with IBS on their own, together, or in alternating periods.

Common symptoms include:[1]

Abdominal pain and cramping

Abdominal pain and cramping, particularly felt in the lower belly, is one of the most common symptoms of IBS. Abdominal cramps can be caused by constipation or diarrhea, other symptoms of irritable bowel syndrome. They typically increase after meals. For some people affected by IBS, having a bowel movement (BM) can intensify pain and cramping; for others, having a BM can reduce these symptoms.

Irritable bowel syndrome (IBS) with predominant diarrhea

Some people experience diarrhea as a main symptom of irritable bowel syndrome, passing loose, watery stools more than three times per day. In people with IBS, diarrhea may occur suddenly, particularly after encountering triggers of their symptoms. In cases of irritable bowel syndrome in which a person experiences diarrhea as one of their most prominent symptoms, the condition is sometimes called IBS-D. Altering a person’s diet is the first-line treatment for IBS-D, followed by prescribing medications.[^4]

Irritable bowel syndrome (IBS) with predominant constipation

Those experiencing constipation as a symptom of IBS may pass fewer than three bowel movements per week. When it is passed, stool is often small and hard. When a person experiences constipation as one of the principal symptoms of their irritable bowel syndrome, this is sometimes called IBS-C.

Good to know: IBS-C shares many symptoms ‒ including bloating, abdominal pain and infrequent, difficult bowel movements ‒ with another common gastrointestinal disorder, chronic idiopathic constipation (CIC). Current research suggests that that IBS-C and CIC are different conditions, despite their significantly overlapping symptoms. If a person seeks medical attention for constipation, doctors will ensure that appropriate testing is undertaken so that a differential diagnosis can be made, as these conditions require different treatment approaches to relieve constipation.[2]

Irritable bowel syndrome (IBS) with constipation and diarrhea

When a person is equally affected by constipation and diarrhea as symptoms of irritable bowel syndrome, this is called IBS-M (mixed irritable bowel syndrome) or IBS-A (alternating irritable bowel syndrome.

Rectal tenesmus

Rectal tenesmus involves cramping and spasms in the rectum. This leads to feeling that a bowel movement is incomplete, even if the bowel has actually been evacuated successfully. This feeling may lead to abdominal pain and cramping, associated with straining to bring about a bowel movement.

Good to know: Tenesmus is a symptom of many other gastrointestinal conditions, as well as a symptom of IBS. If a person seeks medical attention for rectal tenesmus, doctors will check for inflammation of the colon, to rule out a diagnosis such as ulcerative colitis (a form of IBD) or colon cancer.

Bloating and gas

Many people with IBS experience intense bloating (a sensation of increased abdominal pressure). This may or may not be due to an increased quantity of gas in the gastrointestinal tract; about 50 % of people experience increased abdominal pressure without a buildup of gas.[3]

Some people with irritable bowel syndrome also experience increased burping.

Mucus in stool

Passing mucus in the stool is a common symptom of IBS, but passing blood may indicate a more serious condition affecting the bowel, colon or gastrointestinal tract. Always seek medical attention for a prompt diagnosis if blood is present in bowel movements.


  1. Diagnosis and treatment of diarrhea-predominant irritable bowel syndrome.” International Journal of General Medicine. 11 February 2016. Accessed: 27 April 2018.

  2. Chronic Constipation and Constipation-Predominant IBS: Separate and Distinct Disorders or a Spectrum of Disease?” Gastroenterology & Hepatology. March 2016. Accessed: 27 April 2018.

  3. Bloating.” The IBS Network. 2018. Accessed: 27 April 2018.