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Irritable Bowel Syndrome (IBS) Center

Signs and Symptoms of IBS

author image William Salt, M.D.
William B. Salt II, M.D., is a practicing gastroenterologist and founder of IBS and Microbiome Solutions in Columbus, Ohio. He is an adjunct assistant professor of medicine at The Ohio State University. Dr. Salt's passion and specialty is the care and education of patients suffering with irritable bowel syndrome (IBS). His most recent book is "IBS Irritable Bowel Syndrome: A Gastroenterologist Answers Your Questions."

IBS is a chronic disease recognized by at least six months of symptoms of abdominal pain and/or discomfort associated with bowel dysfunction (constipation, diarrhea or both). Most with IBS also have “gas” symptoms, and many have abdominal bloating. Eating triggers symptoms for many. IBS can be associated with other GI and bodily pain conditions, as well as with symptoms of emotional distress.


Disease is dysfunction, which is disturbance of the body’s normal function and activities. Symptoms and signs are the expression. A symptom is subjective evidence of disease experienced by an individual and known to others and health care professionals only if reported. A sign is objective evidence of disease, such as blood in the stool or an abdominal mass, which can be recognized by others and health care professionals.

Describing Symptoms

There are two tools that can help patients describe their symptoms to doctors:

The Bristol Stool Form Scale describes seven types of stool with a visual depiction of each, readily available on the Internet. The seven types are:

Type 1: Separate hard lumps like nuts (hard to pass); Type 2: Sausage-shape, but lumpy; Type 3: Like a sausage, but with cracks on its surface; Type 4: Like a sausage or snake, smooth and soft; Type 5: Soft blobs with clear-cut edges (passed easily); Type 6: Fluffy pieces with ragged edges, a mushy stool; Type 7: Watery, no solid pieces, entirely liquid.

The MyGIHealth Mobile App is free and based upon extensive research by the National Institutes of Health. It is designed by doctors to provide expert tools for patients to assess and monitor symptoms.

Abdominal Pain and Discomfort

Abdominal pain in IBS can be located anywhere in the belly and can radiate into the upper legs, back or chest. Many with IBS describe the symptoms as discomfort rather than pain.

Bowel Dysfunction

Bowel symptoms are the basis for categorizing IBS into subtypes, and determination of the IBS subtype is important for selecting the appropriate diagnostic tests and treatment strategies. It is important to determine the subtype symptom pattern without influence of treatments, such as laxatives and antidiarrheal agents. Stool consistency correlates better with recognition of constipation and diarrhea than does stool frequency.

The four IBS subgroups are: IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), IBS with mixed or alternating diarrhea and constipation (IBS-M) and IBS post infectious (IBS-PI). Many IBS-M patients report days without a bowel movement or with only small, hard stools. These are followed by periods of multiple stools of variable consistency interpreted and reported as “diarrhea.” Most of these patients actually have IBS-C, with periods of progressive stool accumulation ultimately resulting in bowel hyperactivity and purging.

Pain Along With Bowel Dysfunction

Recognition of the symptoms of IBS depends upon the presence of both abdominal pain and/or discomfort as well as bowel dysfunction: improvement with defecation, onset associated with a change of stool frequency or onset associated with a change in stool form or appearance. So abdominal pain without bowel dysfunction cannot be diagnosed as IBS. However, many patients do not necessarily report a close association of pain with bowel dysfunction. For example, they can have pain one day without bowel dysfunction.


Most patients with IBS also experience gas symptoms. Gas symptoms include abdominal bloating and flatulence, which can create a bad odor. It can be normal to pass flatus up to 21 times a day. The sign is abdominal distention, which is actual enlargement.

Relationship With Food

At least 50 percent of patients with IBS describe urgent, sometimes unexpected and inconvenient bowel movements after eating. Diarrhea, abdominal pain and abdominal bloating and distention are common. Eating stimulates exaggerated small intestinal and colonic contractions (motility, or peristalsis) in a hypersensitive gut.

While a true food allergy is relatively rare in adults, many IBS patients describe food intolerances and sensitivities, including gluten (wheat, barley and rye), dairy/lactose and certain poorly absorbed carbohydrates.

Natural History

IBS is a chronic relapsing disease in most patients in which symptoms may vary over time relative to pain location and stool pattern. However, the number of people with IBS appears to decline with age. Predictors of worse outcomes include previous surgery, longer duration of disease, multiple bodily pain symptoms and coexisting (comorbid) anxiety and depression. Once a secure diagnosis of IBS has been made, the risk of a later alternative disease diagnosis, such as inflammatory bowel disease or colorectal cancer, is less than 5 percent.

It is common for IBS patients to migrate between different subtypes over time, most commonly from IBS-C or IBS-D to IBS-M. IBS-PI can be reactivated or exacerbated by bacterial food poisoning.

Associated Symptoms

Multiple symptoms and conditions commonly co-occur with IBS. These include other functional GI disorders, or FGIDs (such as functional reflux and dyspepsia/epigastric pain nonresponsive to strong acid reducers; IBS is the most common FGID), somatic symptom syndromes, which are bodily pain disorders (such as chronic headaches, fibromyalgia and chronic pelvic pain) and emotional distress (anxiety and depression).

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