OBJECTIVE:To evaluate the effect on influenza virus of Jinchai,a capsule made of Traditional Chinese Medicine.METHODS:Madin-darby canine kidney(MDCK) cells were infected with the FM1 strain of influenza virus A(subtype H1N1) in vitro.They were used to explore how Jinchai affected cell adsorption,cell membrane fusion,transcription and replication of the influenza virus.Hemagglutinin(HA) protein,intracellular pH,and influenza virus protein acid(PA) polymerase subunit were detected with confocal microscopy and real-time fluorescent quantitative polymerase chain reaction.RESULTS:Jinchai significantly reduced the expression of HA and PA polymerase subunit mRNA in infected MDCK cells.Jinchai also significantly decreased intracellular pH in infected cells.CONCLUSIONS:Jinchai had strong anti-influenza activity against the influenza virus.It weakened the ability of the influenza virus to adsorb to cell wall and fuse with cell membranes in the early infection stage,and inhibited the transcription and replication of the virus.