Diarrhea is a common condition in neonatal calves and can be caused by a wide variety of infections and noxious agents. Oral electrolyte therapy is a simple and economical method of treating diarrheic calves. Oral electrolyte solutions can correct dehydration and acidosis, and they may also have a role in preventing or alleviating mucosal damage. Indications, the principles of administration, and choosing an electrolyte product are discussed with examples.