Living organisms are composed of millions different molecules.Both hydrophilic and hydrophobic molecules make up cells and tissues.However,in injured tissues,hydrophobic portions (hyppos) are exposed on the surface of biological molecules.It is currently thought that immune responses are initiated by pathogen-associated molecular pattern or by tissue-derived danger/alarm signals,and the hyppos of molecules can work as danger signals.Since the water-insoluble molecules could form non-productive and even toxic aggregates in aqueous body fluids,they have the potential to disturb homeostasis of living organisms.