Because alcohol dehydrates the body, a good remedy for a hangover is to drink plenty of water. Sports drinks with electrolytes are even better for hydration during a hangover because they restore salt and potassium that the body lost.
To relieve symptoms of nausea during a hangover, ginger is a good remedy. Before drinking, eating fatty foods helps line the intestines with grease, making it harder to absorb alcohol. After drinking, eating easy-to-digest foods, including toast and cereal, helps. If there is nothing to do during a hangover, going back to bed and sleeping it off is an effective remedy.