D5W stands for Dextrose 5% in Water, which is a type of intravenous solution used in medical treatment. It is a form of glucose (sugar) that is used to treat low blood sugar (hypoglycemia), insulin shock, or dehydration. D5W raises total fluid volume and is also helpful in rehydrating and excretory purposes. It is given as an IV injection into a vein. The amount of glucose in D5W (2.5 g in 50 mL or 5 g in 100 mL) is too small to affect blood glucose values.