AbstractInflammation, which constitutes the body's response to injury, is characterized by a series of events where several different cell types are playing distinct roles. Proteinase‐activated receptors (PARs) are expressed in all the cell types that are involved in inflammatory processes. The expression of PARs is up‐regulated during inflammatory processes. Activation of PARs can lead to inflammation or, in some circumstances, can be protective against uncontrolled inflammatory reaction. Most recently, studies have shown that inflammatory responses were altered in PAR‐deficient mice. Thus, a crucial role for PARs seems to emerge from the most recent literature and presents PARs as novel and interesting therapeutic targets for the treatment of inflammation. Drug Dev. Res. 59:375–381, 2003. © 2003 Wiley‐Liss, Inc.