Objective\ To study the effects of ChaiQin Particles for common cold as inhibitor of respiratory syncytial virus (RSV) infection in vitro . Methods\ The anti-RSV effects in HeLa cell line were observed by microcytopathic-inhibiting-test. According to Reed-Muench assay,the effective dose of 50 percentage (IC 50 ) and treatment index(TI) were measured. Results\ Its IC 50 and TI to 100 TCID 50 RSV-Long strain were 31±7.07 mg·L -1 and 28.88±4.05 respectively when diluted by 2-fold series, ...