ABSTRACT
<p><b>OBJECTIVE</b>To study the proportion and mechanism of relieving asthma of drug partnership comprising herbal Ephedrae & Pheretima.</p><p><b>METHOD</b>To study relaxant effect on 10 micromol x L(-1) carbachol (CCh) and 10 micromol x L(-1) histamine (His) precontracted isolated tracheal rings and lowering effect on short-circuit current (Isc) increase induced by 10 micromol x L(-1) CCh with 3 proportions of 1:1, 1:3, 1:9 extract.</p><p><b>RESULT</b>1:3 proportions dose-dependently relaxed CCh-precontracted isolated tracheal rings, IC50 of 1:1, 1:3 is 7.5, 15 mg x mL(-1) respectively, 1:9 could not produce 50% inhibition effect on CCh-evoked contraction; 3 proportions also dose-dependently relaxed His-precontracted isolated tracheal rings, IC50 of 1:9, 1:3 and 1:1 is 0.19, 0.61, 1.8 mg x mL(-1) respectively. On the other hand,the orders potency of the decrease effect on CCh-evoked short circuit current increase is 1:3 > 1:1 > 1:9. The difference is not significant (P < 0.05).</p><p><b>CONCLUSION</b>Herbal Ephedrae & Pheretima had tracheal muscle relaxant and epithelium ion secretion inhibition effect, its mechanism of relieving asthma involved anti-CCh and anti-His effect 1:3 was the most appropriate dosage ratio in the anti-asthmatic drug partnership.</p>