Objective: To compare chemical properties and pharmacodynamics between fine powder and ultra-fine powder of compound Beimu powder. Method: Change of chemical properties from fine powder and ultra-fine powder of Fritillaria ussuriensis

Ephedra sinica and Glycyrrhiza uralensis were investigated by determining the content of water-soluble and alcohol-soluble extract and active ingredients

thin layer chromatography (TLC) was used to identify these compounds. With cough latency and cough times of mice as indexes

antitussive effect of fine and ultra-fine powder was compared by ammonia induced cough in mice test. Result: Studies on chemical properties showed nature and content of main chemical composition from ultra-fine powder were not changed significantly.There was significantly inhibited of ultra-fine powder on mice cough which was caused by ammonia

it was more obvious by compared isodose fine powder of compound Beimu powder. Conclusion: Compared with fine powder

there was no obvious change of main chemical composition

but therapeutic effect improved 2 times

it could be reduce the dose of compound Beimu powder

results from this test would provide references for use of ultra-fine grinding technology in traditional Chinese medicine compound.