Exosomes are small membrane-bound vesicles that are released from many different types of cells, and their size range is from 1000 to 2000 nanometers. They are found in most bodily fluids, including blood, urine, saliva, and breast milk. Exosomes are also enzymes that help digest food within the digestive system. Exosomes are thought to play a role in intercellular communication, as they can transfer their contents (including proteins, lipids, and nucleic acids) to other cells, so they differ from other vesicles inside the cell based on the different functions of the exosomes. This process is thought to be important in the development and progression of many diseases, as well as in normal physiological processes. Exosomes were first described in the late 1970s, but their role in disease was not realized until the early 2000s. Since then, exosomes have been implicated in the development and progression of many different diseases, including cancer, neurodegenerative diseases, and infectious diseases. Exosomes are thought to play a role in cancer by promoting tumor growth, metastasis, and angiogenesis. In neurodegenerative diseases, exosomes are thought to contribute to the spread of pathological proteins, such as tau and alpha-synuclein. In infectious diseases, exosomes are thought to play a role in the immune response, as well as in the transmission of viruses and other pathogens. The study of exosomes is an emerging field, and there is much that is still unknown about these intriguing particles. However, the potential implications of exosomes in disease are significant, and further research is warranted.