Irritable bowel syndrome has three main symptoms:

Abdominal pain

The pain can occur anywhere in the abdomen but is most commonly felt in the lower abdomen. It can be severe. Characteristically, it eases following opening of the bowels. Sometimes the pain comes on after eating. When pain occurs in the upper abdomen, it can be confused with peptic ulcer or gall bladder pain and there may be an overlap with indigestion symptoms (so-called ‘functional dyspepsia’). The site of pain can vary from person to person and even within an individual.

Changes in bowel habit

Both diarrhoea and constipation may occur; sometimes they alternate. Morning urgency is common, where the patient feels an urgent desire to defaecate several times after getting up in the morning and following breakfast, after which the bowels settle. There may be a feeling of incomplete emptying after a bowel movement. The motion is often described as loose and semi-formed rather than watery but may also be described as hard and lumpy. There can be mucus present but not blood.

Bloating

A sensation of bloating is commonly reported and the abdomen often appears visibly distended. Other symptoms also occur regularly including nausea, but vomiting is less common. The patient may complain of apparently unrelated symptoms such as headache, backache, and feeling lethargic and tired. Urinary symptoms may be associated with IBS – for example, frequency, urgency and nocturia (the need to pass urine during the night). Some women report discomfort when having sex (dyspareunia).