Imodium Capsules can stop diarrhoea with one dose, quickly and effectively. Imodium can be used to treat episodes of diarrhoea associated with Irritable Bowel Syndrome (IBS) after your doctor has diagnosed you are suffering from this condition. It is used to treat sudden short-lived (acute) attacks of diarrhoea in adults and children over 12 years old. It works by making the stools more solid and less frequent. Imodium can also be used to treat episodes of diarrhoea associated with Irritable Bowel Syndrome after your doctor has diagnosed you are suffering from this condition.