Exosomes are membrane-bound nano-sized vesicles (30-150 nm in diameter) containing a variety of biomolecules including lipids, proteins, and nucleic acids. Exosomes are released from cells through exocytosis and may be taken up by target cells to transmit biological signals to both local and distant cells. Recent studies have shown that exosomes may affect the process of inflammatory bowel disease (IBD) through affecting both immune-mediated response and barrier function. This review discusses the production, basic composition and function of exosomes. It also summarizes the diagnostic value and therapeutic potential of different components and sources of exosomes in IBD and their emerging roles as delivery vehicles in many diseases.