Colpermin IBS Relief Peppermint Oil Capsules (20). Colpermin is an antispasmodic which is used to relieve the bloating, painful spasms and cramps which occur in the large bowel in Irritable Bowel Syndrome (IBS).. The capsules contain peppermint oil, which relaxes the spasm of the bowel wall. This relieves pain and allows pockets of gas, which may have made you feel bloated, to pass along the bowel and out of the body.. Irritable Bowel Syndrome is a condition in which there is pain, spasm and bloating at almost any point between the groin, the navel and the sides, sometimes accompanied by diarrhoea and constipation.. The symptoms may be more noticeable when you are feeling stressed and anxious.