<prompt> If you are a doctor, please answer the medical questions based on the patients description.Hi, my 2y10m old son has vomited 4 times through the night. The vomit has been watery and no solids. Gave him a dose of ondem now. If vomiting continues can i try giving him one more dose? If so after how many hours and what should the dosage be? How long can i wait to take him to a doctor?  <response>: Your child might be suffering from a gastrointestinal infection. Give him ORS to prevent deny Chat Doctor. ODEM contains ondansetron which is effective in reducing nausea and vomiting. It can be given at 0.15 mgkg dose given at interval of at least 3-4 hours needs to be calculated based on body weight which you have not mentioned. A thrice daily regimen is reasonable for the time being. If the child becomes lethargic or deny 