The exact cause of IBS is unknown. It's likely a combination of:more frequent or stronger squeezing(contractions) of the muscles lining your bowel, increased sensitivity to the gas inside your bowel or your genetic make-up. Psychological factors, eg stress, may trigger your symptoms. Your symptoms may get worse after eating. Specific foods, eg tea, coffee and fatty foods, can also trigger symptoms. Antibiotics and non-steroidal anti-inflammatory drugs, eg ibuprofen and diclofenac, can make symptoms worse.
Attribution: BUPA