[Objectives] To investigate the synergistic effect of Arnebiae Radix after processing. [Methods] The effects of raw Arnebiae Radix and milk processed Arnebiae Radix on hypothermia in yeast-induced febrile rats were compared. [Results] The processed and unprocessed Arnebiae Radix at high, medium and low doses all had a certain effect on inhibiting the rise of body temperature in rats. The high dose unprocessed group, the medium dose processed group and the high dose processed group had the best inhibitory effect on body temperature, the low dose processed group could delay the fever time, and the low dose unprocessed group had poor inhibitory' effect on fever. [Conclusions] The prepared Arnebiae Radix has enhanced drug effect, and milk processed Arnebiae Radix can be used to replace common Arnebiae Radix to reduce the dosage of Arnebiae Radix and save Arnebiae Radix resources.