Over the last decades exosomes have become increasingly popular in the field of medicine. While until recently they were believed to be involved in the removal of obsolete particles from the cell, it is now known that exosomes are key players in cellular communication, carrying source-specific molecules such as proteins, growth factors, miRNA/mRNA, among others. The discovery that exosomes are not bound to intraspecies interactions, but are also capable of interkingdom communication, has once again revolutionized the field of exosomes research. A rapidly growing body of literature is shedding light at novel sources and participation of exosomes in physiological or regenerative processes, infection and disease. For the purpose of this review we have categorized 6 sources of interest (animal products, body fluids, plants, bacteria, fungus and parasites) and linked their innate roles to the clinics and potential medical applications, such as cell-based therapy, diagnostics or drug delivery.