Hemopure is the only substitution for human blood that has been approved by the FDA. Hemopure utilizes hemoglobin that has been extracted from the blood of cattle and purified. Hemopure is the product of many years of research focused on artificial blood and is likely to be followed by other products. Natural, human blood in all of its complexity has yet to be fully duplicated or replaced by chemical means and is a necessity that hemopure cannot fully replace.