Hi. Thanks for your query. Noted the history about your 6 year old son and understood the concerns. Vomiting followed by loose stools is surely indicative of a gastroenteritis. This may be a stomach flu or can be a bacterial one. The supportive treatment remains the same for either of the conditions as follows. To stop vomiting the medications as would be advised by his Pediatrician. Clinical evaluation and examination by a Pediatrician. Investigations of stool and blood. If there is bacterial infection a course of an antibiotic, metronidazole and probiotics. Plenty of oral fluids, electrolyte solutions and soft diet after the vomiting stops. If the vomiting does not stop, he will need an admission to the hospital for intravenous fluids and antibiotics.