There are two possible causes for the occurrence of low-grade fever and vomiting. One is caused by an upper respiratory tract infection and a complication of gastritis, and it may also be a type of gastrointestinal cold. In this case, we can test the blood test to determine whether it is a viral or bacterial infection. In addition, the diet must be light, you can temporarily do not eat some food, drink a little liquid porridge or juice, you can take appropriate probiotics, spleen oral liquid, and vitamin B complex. According to the test results to choose the symptomatic treatment, the etiology of the treatment, to prevent dehydration can also be supplemented with a little rehydration salts, and to adjust the treatment plan at any time to review.