The length of time a vitamin IV drip stays in the body varies depending on the type of vitamins used, as well as how much is delivered into the bloodstream. Generally speaking, most protocols call for an infusion to last anywhere from 15 minutes to two hours. However, some treatments can take up to four or five hours if larger amounts are needed. After the initial dose has been administered, your doctor may also order additional rounds of infusions over several days or weeks so that you receive a cumulative effect from treatment. During this period it's important for patients to drink plenty of fluids and stay hydrated in order to help ensure that their body is able to absorb and utilize all of the nutrients provided by the IV vitamin therapy.