Red blood cells carry waste from the cells to the lungs. Once this happens, the lungs remove the waste from the body by exhalation.
Red blood cells are the type of blood which carry waste product from the cells, in the form of carbon dioxide, to the lungs. The waste is then removed from the cells of the body, and brought to the lungs to be released during exhalation (or breathing out). Red blood cells also bring oxygen from the lungs to the cells, so that they are refreshed. They are a very important component within the body. That is why there are so many in blood — in fact, there are 5 million red blood cells in just one drop of blood.