ABSTRACT
Decoction is a traditional clinical way of traditional Chinese medicine （TCM） compound. A series of complex physical and chemical changes are often involved in the process of decoction， which presents a mixed-phase system. In most studies on the TCM compound decoction， it has always focused on the amounts of chemical substances in decoction， while the phase properties and existence forms of these components are neglected. Most of the chemical components exist in the mixed-phase system as molecules， ions or other particles. According to the particle size of the contained particles， the differences among the phases， including true solution phase， colloidal phase， suspended phase and precipitated phase， lead to their differences in pharmaceutical and biological effects. Based on the above research background， this paper takes the phase state differences of decoction as the breakthrough point， and systematically reviews the physicochemical properties， the physical structures of the active components and the biological effects of the decoction caused by the phase state differences. The phase state differences of TCM compound decoction have been found to be closely related to their efficacy， which might be a good perspective to investigate the possible mechanism. It might provide a beneficial reference for the exploration of related basic research on TCM compounds.