Irritable bowel syndrome is also commonly known as spastic colon, mucous colitis, spastic colitis, nervous stomach, or irritable colon.

IBS is a functional disorder, which means that the affected individual is not suffering from any disease, but that the bowel isn't working as it should.

The bowel nerves and muscles are extra-sensitive: the muscles may contract too much after a meal, causing cramping and diarrhoea. Or the nerves can be hypersensitive, causing cramping or pain due to gas.

IBS is more common in women than in men, and the symptoms usually begin at around age 20. For the women, symptoms seem to worsen during their menstrual periods.

IBS can be painful but it does not result in any permanent damage to the intestines or cause any other disease.