Yes, it is important to consult a doctor if your child refuses solid foods and has infrequent urination after having gastroenteritis. The doctor will be able to determine if further tests at the hospital are necessary. It is also important to encourage your child to drink small amounts of fluid and try light foods like toast with a little butter, eggs, soups, and broths. If you have not already done so, speaking to a doctor over the phone may also be helpful.