What causes IBS

The exact cause of irritable bowel syndrome (IBS) remains a mystery and doctors have many theories about what could trigger or aggravate the disorder:

One idea is that there is a problem with how the muscles and nerves work in the gut that make it extra sensitive in people with IBS.
Food does not pass through the intestines in the normal manner and unpredictable movements of the muscles in the gut bring about pain and discomfort.
It has been suggested that IBS may be caused by stomach bugs or food poisoning, or by having an unduly stressful lifestyle.
Eating irregularly or having a less-than-healthy diet often worsens but does not cause IBS. Eating fatty foods and drinking tea and coffee, for instance, are known to aggravate symptoms.
The use of certain medications, such as antibiotics or drugs used to treat the pain of arthritis may also make IBS worse but probably do not cause the condition.

Doctors agree, however, that it is unlikely that there is a single reason for why one person develops IBS while another may not. It follows that treatment relies on alleviating the symptoms of IBS.