Some oral rehydration solutions come in packets and just need to be mixed with clean water. Oral rehydration solution can also be made at home. If the water in the area is not safe, it can be boiled to make it safe. (Boiling the water will kill any bacteria, viruses, or parasites in the water.) Salt and sugar are then mixed into the water. Drinking this mixture, after the water cools, will re-hydrate the child, if he drinks enough. Adding a banana or orange juice can add potassium to the mixture.