Rehydration, Adult

Rehydration is the replacement of body fluids lost during dehydration. Dehydration is an extreme loss of body fluids to the point of body function impairment. There are many ways extreme fluid loss can occur, including vomiting, diarrhea, or excess sweating. Recovering from dehydration requires replacing lost fluids, continuing to eat to maintain strength, and avoiding foods and beverages that may contribute to further fluid loss or may increase nausea.


In most cases, rehydration involves the replacement of not only fluids but also carbohydrates and basic body salts. Rehydration with an oral rehydration solution is one way to replace essential nutrients lost through dehydration.

An oral rehydration solution can be purchased at pharmacies, retail stores, and online. Premixed packets of powder that you combine with water to make a solution are also sold. You can prepare an oral rehydration solution at home by mixing the following ingredients together:

  • ⅓–⅔ tsp table salt.

  • ¾ tsp baking soda.

  • ⅓ tsp salt substitute containing potassium chloride.

  • 1 ⅓ tablespoons sugar.

  • 1 L (34 oz) of water.

Be sure to use exact measurements. Including too much sugar can make diarrhea worse.

Drink ½–1 cup (120–240 mL) of oral rehydration solution each time you have diarrhea or vomit. If drinking this amount makes your vomiting worse, try drinking smaller amounts more often. For example, drink 1–3 tsp every 5–10 minutes.

A general rule for staying hydrated is to drink 1½–2 L of fluid per day. Talk to your caregiver about the specific amount you should be drinking each day. Drink enough fluids to keep your urine clear or pale yellow.


Even if you have had severe sweating or you are having diarrhea, do not stop eating. Many healthy items in a normal diet are okay to continue eating while recovering from dehydration. The following tips can help you to lessen nausea when you eat:

  • Ask someone else to prepare your food. Cooking smells may worsen nausea.

  • Eat in a well-ventilated room away from cooking smells.

  • Sit up when you eat. Avoid lying down until 1–2 hours after eating.

  • Eat small amounts when you eat.

  • Eat foods that are easy to digest. These include soft, well-cooked, or mashed foods.


Avoid eating or drinking the following foods and beverages that may increase nausea or further loss of fluid:

  • Fruit juices with a high sugar content, such as concentrated juices.

  • Alcohol.

  • Beverages containing caffeine.

  • Carbonated drinks. They may cause a lot of gas.

  • Foods that may cause a lot of gas, such as cabbage, broccoli, and beans.

  • Fatty, greasy, and fried foods.

  • Spicy, very salty, and very sweet foods or drinks.

  • Foods or drinks that are very hot or very cold. Consume food or drinks at or near room temperature.

  • Foods that need a lot of chewing, such as raw vegetables.

  • Foods that are sticky or hard to swallow, such as peanut butter.