IV vitamin C therapy is the administration of a high dose of vitamin C administered intravenously. It is an antioxidant that aids in preventing oxidative stress, which essentially strengthens the immune system. Since humans cannot produce vitamin C, it is a nutrient that they must receive from food or supplements. High dose vitamin C can be taken orally, or it delivered through IV infusion. In this process, vitamin C enters the bloodstream directly through the veins. IV vitamin C treatments allow for the nutrient to reach higher levels within the body, as absorption occurs much more quickly.