The fact that a child vomiting keeps asking for water means that the child is mildly dehydrated. The vomit is electrolyte fluid, which contains sodium, potassium or other anionic components, so it is always hydrated, pure boiled water, plain water does not help, it will only cause gastric retention, but can not replenish body fluids. The summary is that when a child vomits a lot, the skin is already dry, the oral fluid in the mouth is low, the urine is low, or there are fewer tears in the eyes and the eyes are deeply sunken, which already indicates a mild dehydration. If you do not continue to vomit, you can drink some rice soup, rice soup with a little salt, a little light salt is the best thing for rehydration, a little bit of drinking, do not drink the stomach retention, stomach retention will lead to vomiting again, remember. In the case of special vomiting can not stop, quickly go to the hospital for fluids, because if once the mild dehydration is followed by moderate. When you are moderately dehydrated, your blood vessels are collapsed and even needles can’t get into the veins, so going to the hospital is the best way to go at this time.