There are four kinds of intravenous fluids that may be used for severe dehydration. Ringer's lactate is probably the most readily available throughout the world and gives quite satisfactory results. The Diarrhoea Treatment Solution is ideal but it may not be available in some countries. Half-strength Darrow's solution has been used extensively for childhood dehydration in treatment centres throughout the world; its major disadvantage is its low sodium concentration. As a last resort if nothing else is available, normal saline may be used. All of these, and particularly the last, should be supplemented by ORS as soon as the patient can drink.