What is Loperamide Hydrochloride, and when is it used? Loperamide is a medicine to treat Diarrhoea (runny poo). It can also help with short term diarrhoea or irritable bowel syndrome (IBS). Loperamide is also used for long-lasting Diarrhoea from bowel problems such as Crohn's disease, ulcerative colitis and