To evaluate the hot/cold characteristics of Aaí.Methods:MTT cell proliferation inhibition assay was performed to study Aaí's effect on cell proliferation.Inverted phase contrast microscopy was applied to study Aaí's effect on cell morphological features.Trypan Blue staining exclusion assay was used to compare and analyze Aaí's cytotoxicity.A further determination of cellular NADH level and NADH/NAD+ ratio via spectrophotometry was performed to analyze Aaí's effect on cell energy metabolism.Results:Within the range of preset concentrations,Aaí and Cortex Phellodendri demonstrated divergently inhibitive effects on cell growth,proliferation and energy metabolism of the two hepatic cell strains.In the MTT assay,Aaí showed significant (P<0.05) or highly significant (P<0.01) inhibitive effect on cell proliferation at concentrations≤0.5 μg/mL and≥10 μg/mL.Microscopic examination showed corresponding results of lower cell density,attenuated granularity,and more outstretched cells in irregular polygonal shape could be observed.Trypan Blue staining assay showed that any concentration of Aaí had no obvious toxicity to the cells,which was similar to Cortex Phellodendri.Aaí with any preset concentrations was also found to be significantly (P<0.05) or highly significantly (P<0.01) reducing intracellular NADH level as well as NADH/NAD+ ratio.Conclusion:The effects of Aaí on cell lines HepG2 and Hep3B are similar to that of Cortex Phellodendri Chinensis,and can reduce energy metabolism.This study proves that the medicinal property of Aaí is cold or cool.