Gastroenteritis (also known as gastric flu or stomach flu, although unrelated to influenza) is inflammation of the gastrointestinal tract, involving both the stomach and the small intestine and resulting in acute diarrhea. It can be transferred by contact with contaminated food and water. (wiki)

This condition does not last that long. It’s n0t dangerous but parents should be very concern on their kids as vomiting and diarrhea can cause dehydration.

Below are some necessary measure that kidshealth.org offered to us. You can just click the link to know more about it or read on as I copied some of the texts found there.

The following text below are not my own as this are direct copy from kidshealth.org:

For Infants Under 6 Months

• Avoid giving plain water to a young infant unless your doctor directly specifies an amount.
• Offer your infant small but frequent amounts — about 2 to 3 teaspoons, or up to ½ ounce (about 20 milliliters) — of an oral electrolyte solution every 15 to 20 minutes with a spoon or an oral syringe. Oral electrolyte solutions (available at most supermarkets or pharmacies and also called oral electrolyte maintenance solutions) are balanced with salts to replace what’s lost with vomiting or diarrhea, and they also contain some sugar. It’s especially important for young infants that any fluids given have the correct salt balance (unflavored electrolyte solutions are best for younger infants).
• Gradually increase the amount of solution you’re giving if your infant is able to keep it down for more than a couple of hours without vomiting. For instance, if your little one takes 4 ounces (or about 120 milliliters) normally per feed, slowly work up to giving this amount of oral electrolyte solution over the course of the day.
• Do not give more solution at a time than your infant would normally eat — this will overfill an already irritated tummy and will likely cause more vomiting.
• After your infant goes for a period of time (more than about 8 hours) without vomiting, reintroduce formula slowly if your infant is formula-fed. Start with small (½ to 1 ounce, or about 20 to 30 milliliters), more frequent feeds and slowly work up to the normal feeding routine. If your infant already eats baby cereal, it’s OK to start solid feedings in small amounts again.
• If your infant is exclusively breastfeeding and vomits (not just spits up, but vomits what seems like the entire feed) more than once, then breastfeed for a total of 5-10 minutes every 2 hours. If your infant is still vomiting, then call your doctor. After 8 hours without vomiting, you can resume breastfeeding normally.
• If your infant is under 1 month old and vomiting all feeds (not just spitting up), call your doctor immediately.

For Infants 6 Months to 1 Year

• Avoid giving plain water to an infant under 1 year unless your doctor directly specifies an amount.
• Give your infant small but frequent amounts — about 3 teaspoons, or ½ ounce (about 20 milliliters) — of an oral electrolyte solution every 15-20 minutes. It’s important that any fluids given to infants under 1 year of age who are vomiting have the correct salt balance (again, oral electrolyte solutions are balanced with salts to replace what’s lost with vomiting or diarrhea).
• An infant over 6 months of age may not appreciate the taste of an unflavored oral electrolyte solution. Flavored solutions are also available, or you can add ½ teaspoon (about 3 milliliters) of juice to each feeding of unflavored oral electrolyte solutions. Frozen oral electrolyte solution pops are often appealing to infants in this age group; this approach also encourages the slow intake of fluids that’s required.
• Gradually increase the amount of solution you’re giving if your infant is able to keep it down for more than a couple of hours without vomiting. For instance, if your infant takes 4 ounces (about 120 milliliters) normally per feed, work slowly up to giving this amount of oral electrolyte solution over the course of the day.
• Do not give more solution at a time than your infant would normally eat — this will overfill an already irritated tummy and will likely cause more vomiting.
• After your infant goes more than about 8 hours without vomiting, you can reintroduce formula slowly to your infant. Start with small (1 to 2 ounces, or about 30 to 60 milliliters), more frequent feeds and slowly work up to the normal feeding routine. You can also begin small amounts of soft, bland foods that your infant is already familiar with such as bananas, cereals, crackers, or other mild baby foods.
• If your infant doesn’t vomit for 24 hours, you can resume your normal feeding routine.

For Kids 1 Year and Older:

• Give clear liquids (milk and milk products should be avoided) in small amounts (ranging from 2 teaspoons to 2 tablespoons, or up to 1 ounce or 30 milliliters) every 15 minutes. Clear liquids that are appropriate include:
  • ice chips or sips of water
  • flavored oral electrolyte solutions, or add ½ teaspoon (about 3 milliliters) of nonacidic fruit juice to the oral electrolyte solution
  • frozen oral electrolyte solution pops
• If your child vomits, then start over with a smaller amount of fluid (2 teaspoons, or about 5 milliliters) and continue as above.
• If there’s no vomiting for approximately 8 hours, then introduce bland, mild foods gradually. But do not force any foods — your child will tell you when he or she is hungry. Saltine crackers, toast, broths, or mild soups (some noodles are OK), mashed potatoes, rice, and breads are all OK.
• If there’s no vomiting for 24 hours, then you can slowly resume the regular diet. Wait 2 to 3 days before resuming milk products.

It is very important that parents observe their kids and never ever PANIC.