**Abstract**

This chapter focuses on the biology of red blood cell extracellular vesicles (RBCEVs) in normal and diseased conditions, and the potential application of RBCEVs in treatment. Extracellular vesicles (EVs) refer to membranous vesicles secreted by cells into the extracellular environment. EV biology belongs to a rapidly developing field in biomedical sciences. EVs represent a natural mode of cell-to-cell communication, which makes them suitable for delivery of therapeutic agents, such as nucleic acids and proteins, in the body. In particular, RBCEVs feature a wide range of benefits in drug delivery as compared to extracellular vesicles derived from other cell types. In comparison to other delivery systems currently available, RBCEVs are nontoxic, low immunogenic, conveniently obtainable, and easy to use and store. Therefore, RBCEVs boast promising and exceptional advantages in overcoming various limitations of conventional therapeutics.

**Keywords:** extracellular vesicles, red blood cells, therapy, drug delivery
