Make sure the child gets plenty of fluids. If a child loses too much body water, he or she may need to be put in the hospital and given IV fluids. The greatest danger is loss of too much water and salt from the body. Give the child an oral rehydration solution that you can buy at a drug, grocery, or discount store without a prescription. It has the right amounts of water, salts, and sugar to replace the lost water.
Some solutions come in fruit and bubble gum flavors.
Use the solution as it comes. Don't add water or sugar. Give small, frequent feedings. Use a teaspoon, especially if the child is vomiting. Start with 1 teaspoon of fluid every 2 or 3 minutes.