ANTIDIARRHEAL AGENTS are drugs used to prevent the onset of diarrhoea, or assist in treating it if the symptom is already present. The main medical treatment while diarrhoea lasts should be the replacement of lost fluid and electrolytes, OPIOID RECEPTOR AGONISTS, such as codeine, morphine, diphenoxylate and loperamide, are efficient as antidiarrhoeals: they are essentially antimotility agents, reducing peristalsis of the intestine, which slows down the movement of faecal material and also promote reabsorption of electrolytes and water. Other agents are adsorbent materials that work in to bind faecal material into solid masses. Such mixtures include those containing kaolin or methylcellulose; preparations which may also be useful in controlling faecal consistency for patients who have undergone colostomy or ileostomy.

Diarrhoea is also part of some inflammatory disorders, such as irritable bowel syndrome, ulcerative colitis and Crohn’s disease. These may best be relieved by treatment with corticosteroids and aminosalicylates. Diarrhea is commonly associated with bacterial or other pathogenic infections (e.g. food poisoning) and these may require treatment with antibiotics or other antimicrobials.