 [ Symptoms ] i have been throwing up constantly for the past 6 hours should i go to the er to get an iv for rehydration [ Disease ] most normal weight adults will not become dehydrated from vomiting in six hours so you may not need iv fluid replacement but you would definitely benefit from some anti vomiting medications like zofran ondanstetron the er team can provide that for you or perhaps your own doctor or the on call doctor will call it in for you signs of dehydration include lack of tearsmoisture in the eyes lack of saliva decreased or absent urine flow and tenting if yoju pull up a flap of skin it should snap flat again with elastic intensity if it remain up like tent this is a sign of severe dehydration