ObJective: To determine fast the content of paeonol in Liuwei Dihuang pills from different manufacturers by near-infrared spectroscopy (NIRS). Method: Near-infrared spectra of different batch of Liuwei Dihuang pills from different manufacturers were collected. Based on the reference values measured with HPLC

the quantitative calibration model of paeonol was built with near-Infrared spectrometry combined with partial least squares (PLS). Result: The internal cross validation proved that the correlation coefficient (R2) was 0.952 1 and the root-mean-square error of cross-validation (RMSECV) was 0.020 93; By the verification of the external validation samples

the root-mean-square error of prediction (RMSEP) was 0.099 7 and the average recovery was 100.38%. Conclusion: The predicting model was accurate and credible. The proposed method could be used in predicting the content of paeonol in Liuwei Dihuang pills. The simple

fast and non-destructive NIRS combined with PLS can provide a new approach to determine rapidly the content of paeonol in large numbers of samples.