Irritable bowel syndrome (IBS) is a common, long-term condition of the digestive system. Symptoms can include stomach cramps, bloating, diarrhoea and/or constipation. The condition is often lifelong, although the symptoms may change over time. With the right strategies, IBS can be successfully managed. IBS does not pose a serious threat to your physical health and does not increase your chances of developing cancer or other bowel-related conditions. The exact cause of IBS is unknown. Many causes have been suggested but none have been proven to lead to IBS.