Every summer, apart from respiratory infections, acute gastroenteritis is the most common cause of salmonella, adenovirus, enterovirus, etc. Patients may experience vomiting and diarrhea, abdominal pain, fever, and even severe abdominal cramping pain, high fever and chills, and anorexia and lethargy. Generally speaking, it takes about three to seven days to treat acute gastroenteritis. In addition to taking medication and fasting for twelve to twenty-four hours, patients may become dehydrated because of incessant diarrhea, so when they see a gastroenterologist, the doctor usually recommends fasting for half a day or a day and more hydration. ”However, doctors also remind that hydration is not just about drinking plain water, it is better to drink electrolyte water solution with appropriate salt and water, if you drink plain water desperately, it may lead to electrolyte deficiency in the body and cause cramps. It is worth noting that the child may vomit. It is worth noting that children who have vomiting and diarrhea lose not only water but also electrolytes, so it is best to supplement with “rehydration salts” sold in pharmacies rather than pure plain water. Some parents just give their children plain water, but the result is dilution of electrolytes in the body, resulting in cramps and other “water poisoning”. The sports drinks on the market also have salt, but the sugar content in the drinks is also high, which can make diarrhea persistent in children with diarrhea. As for “rehydration salts”, they contain the right amount of sugar and salt, which can replenish the water and salt lost from vomiting and diarrhea, and will not cause persistent diarrhea due to excessive sugar. What are “rehydration salts”? ORS for short, each bag contains 1.75 grams of sodium chloride and 11 grams of anhydrous glucose; the sachet contains 0.75 grams of potassium chloride and 1.25 grams of sodium bicarbonate, plus 500 ml (about two teacups) of warm boiled water for use. The osmotic pressure of this solution is close to that of plasma, which is conducive to the absorption of sodium, while the concentration of sugar is set at 2-3% is appropriate, too high concentration will cause osmotic diarrhea. How to give “rehydration salts” to children? When using oral ORS solution, newborns should be given two parts of ORS plus one part of water, at the age of <2