Irritable Bowel Syndrome (IBS) is one of the leading causes of chronic pain both world-wide and in Australia for which there is a lack of treatments. Chronic pain arises from nerve fibres in the colon wall, which fail to 'reset' back to normal following inflammation. Targeting these nerve endings with drugs is a key advance in IBS treatment. This project will identify selective oxytocin analogues that act in the colon to lower pain in sensory nerves thus providing efficacious pain relief in IBS.