Children who want to vomit after falling asleep may be related to factors such as abdominal cold, improper diet and acute gastroenteritis. 1. Cold abdomen: If the child’s abdomen is cold after falling asleep, stimulating the gastrointestinal tract to vigorous peristalsis, and because of sleeping in the supine position, it is likely to want to vomit. 2. Improper diet: If a child eats a lot of greasy, starch-rich food that is difficult to digest before going to bed at night, and the food accumulates in the gastrointestinal tract after the child falls asleep, resulting in an accumulation of food, which may cause the child to want to vomit. 3. Acute gastroenteritis: If a child falls asleep in the middle of the night because of bacterial, viral or parasitic infections leading to an attack of acute gastroenteritis, nausea, vomiting, abdominal pain, diarrhea and other symptoms will occur. If a child wants to vomit after falling asleep, it is necessary to go to the regular hospital in time to identify the cause of the disease, and under the guidance of a professional doctor to choose a suitable method of treatment.