At any one time as many as one in 10 people have symptoms of irritable bowel syndrome. It mainly affects younger adults and is more common in women. Many patients have intermittent symptoms over many years.

The three main features are abdominal pain, a change in stool consistency and abdominal bloating. Constipation is a common problem.

Many patients have investigations at the onset of their symptoms, but no abnormalities are found. The cause is unknown but one theory suggests that IBS occurs due to miscommunication between the brain and the gut, and that gut co-ordination is affected (dysmotility) and it is hypersensitive to stretching, which causes pain. The condition can sometimes develop after a bout of gastroenteritis.

Some sufferers may have a food intolerance that sets off their symptoms. It often seems to be triggered by stress. Many people with IBS also have symptoms of anxiety and depression.

When a patient first presents with symptoms, referral to a GP is usually indicated so that potentially serious causes can be ruled out.

Once an IBS diagnosis has been made, pharmacy management is appropriate and also convenient.

Key facts

• After an initial diagnosis of IBS, most people (up to three-quarters) do not consult a doctor
• IBS has three main symptoms: abdominal pain, changes in bowel habit and bloating
• Patients may need to try various therapies until they find those that suit them
• Antispasmodics are the mainstay of OTC treatment.