<p><b>OBJECTIVE</b>To further study the characteristics of drugs with neutral property in two-way application and conditioned dominance by observing the action characteristic of 10 traditional Chinese medicines with neutral property in hemorheological indicators of heat stagnation and blood stasis syndrome and cold stagnation and blood stasis syndrome rats.</p><p><b>METHOD</b>The model of heat stagnation and blood stasis syndrome rats was established by injecting carrageenan and dry yeast, while the model of cold stagnation and blood stasis syndrome rats was established by body freezing. Subsequently, 10 traditional Chinese medicines with neutral property, 5 traditional Chinese medicines with heat property and 5 traditional Chinese medicines with cold property were selected for intervention to observe the changes in such indicators as whole blood viscosity, plasma viscosity and hematocrit and analyze the action characteristics of drugs with neutral property.</p><p><b>RESULT</b>ANOVA showed that among six of the 10 traditional Chinese medicines with neutral property, including Typhae Pollen, Sarcandrae Herba and Sappan lignum, could obviously increase the hemorheological indicators of both heat stagnation and blood stasis syndrome and cold stagnation and blood stasis syndrome rats; five traditional Chinese medicines with cold property, such as Salviae Miltiorrhizae Radix et Rhizoma, Leonuri Herba, Rhei Radix et Rhizoma, could significantly ameliorate the hemorheological indicators of heat stagnation and blood stasis syndrome rats (P < 0.01 or P < 0.05), and Salvia Miltiorrhiza Radix et Rhizoma alone could ameliorate the hemorheological indicators of cold stagnation and blood stasis syndrome rats (P < 0.05); all of the five traditional Chinese medicines with heat property could significantly ameliorate the hemorheological indicators of cold stagnation and blood stasis syndrome rats (P < 0.01), among which Carthami Flos and Notoginseng Radix et Rhizoma could significantly ameliorate the hemorheological indicators of cold stagnation and blood stasis syndrome rats. According to the average high-shear blood viscosity analysis, drugs with neutral property showed similar action characteristics to those with cold property in ameliorating hemorheology indicators of heat stagnation and blood stasis syndrome rat and better effect than those with heat property in reducing whole blood viscosity; and traditional Chinese medicines with neutral property have the similar action characteristics to those with heat property in improving the hemorheology indicators of cold stagnation and blood stasis syndrome rat and better effect than those with heat property in reducing whole blood viscosity.</p><p><b>CONCLUSION</b>Under the condition of heat stagnation and blood stasis syndrome, traditional Chinese medicines with neutral property show the similar action characteristics to those with cold property; but under the condition of cold stagnation and blood stasis syndrome, traditional Chinese medicines with neutral property show the similar action characteristics to those with heat property. This indicates that traditional Chinese medicines with neutral property show both heat and cold properties under he conditions of heat stagnation and blood stasis syndrome and cold stagnation and blood stasis syndrome.</p>