My son was first vomiting none stop on July 1st. We went to the hospital, they checked him over put him on an IV drip and he was great afterward. He then got sick again August 4. He was away at school and finally after a few days went to the ER they put him on a drip checked his kidneys gave him some gravol and eventually he felt better. Last night he phoned and he is throwing up again. Can a virus keep coming back like this or would it be something else. Something more serious?