Nausea and vomiting are symptoms of an underlying disease and not specific illness. There is a sensation of unease and discomfort in the stomach and the urge to vomit.
It could be caused by acute gastritis, in association with other illnesses, medicines being taken, obstruction of the bowel.My best advice is to counter it by taking natural supplementationin heavy dose. Take ionized water, at least 8 glasses a day.