What is gastroenteritis (stomach infection)?

Gastroenteritis is an upset stomach. It causes nausea and vomiting. You may also have diarrhea or a fever. It is sometimes called "stomach flu," but it is not the flu. Germs like viruses and bacteria can cause it.

You can catch it from someone else who has it, or you can get it from food poisoning. Food poisoning can happen if you eat foods that contain harmful germs. Germs can get into food while the food is growing, during processing, or when it is prepared. You may have become ill after eating meat or eggs that weren't cooked enough or by eating other unsafe foods or drinking unsafe water.

You will probably begin to feel better in 1 or 2 days, but you might feel bad for a week. In the meantime, get plenty of rest, and make sure you do not become dehydrated. Dehydration occurs when your body loses too much fluid. This can happen when you throw up a lot or have diarrhea.

Here are some things you can do to help you feel better.

• Drink plenty of fluids. Choose water and other clear liquids until you feel better. If you have kidney, heart, or liver disease and have to limit fluids, talk with your doctor before you increase how much fluid you drink.
• Drink fluids slowly, in frequent, small amounts. Drinking too much too fast can cause vomiting.
• Use an electrolyte replacement drink (such as Pedialyte or Rehydralyte) to replace fluids and minerals, especially if vomiting or diarrhea lasts longer than 24 hours.
• When you feel like eating again, start with small amounts of food.

Watch closely for any new or worse symptoms, such as fever, belly pain, or signs of dehydration. Be sure to contact your doctor if you have any problems or aren't getting better.