Objective:To determin the feasibility of the new technique to dispel Rhizoma Typhon's sting and hot irritation.Method:By the ultramicro-pulverzing technique different diameter of ultro-powder particles were used for the compared studies through pharmacologic experiments such as mouse acute toxicity test

rabbit conjunctiva stimulation and sedation tests

etc between the raw Rhizoma Typhon、the old and the new processed Rhizoma Typhon.Result:After the ultramicro-powder ing Rhizoma Typhon nearly has the same pharmacological effects as the raw and old processed Rhizoma Typhon

and its toxicity and irritation was less than old processed Rhizoma Typhon

while.Conclusion:The Rhizoma Typhon's sting and irritation was dispelled when with the sting rank of raw RT

old processed method and ultramicro-pulverying method processed by the new technique of ultramicro-pulverization.While pharmacological effects of Rhizoma Typhon can be still retained.