Untreated severe dehydration may cause seizures, permanent brain damage, or death. There are no risks to others. The treatment for dehydration is to rehydrate the body. Drinking fluids usually relieves mild dehydration quickly. If a dehydrated person drinks beverages that contain caffeine , such as teas, soda, and coffee, they may feel worse.
Caffeine causes more urination, so it can undo the benefit of drinking fluids.
Water, sports drinks, and special beverages for children such as Pedialyte help restore hydration and chemical balance. Pedialyte is sold in pharmacies and many food stores. It is mostly water, but also contains salts to prevent chemical imbalances in the blood. A person usually will feel much better once his or her body has been rehydrated. Dehydration is almost always caused by a specific event or disease.