OBJECTIVE:To study the effect of voltage on drug transdermal iontophoresis.METHOD:The enhancing rate(ER) of dicaine hydrochloride with different voltage through rat skin were determined respectively using valia-chien two-chamber diffusion cells.RESULTS:linear regression show that:ER=-3×10 -3 +3.202V,r=0.9979(V is voltage).CONCLUSION:The enhancing rate is proportion to voltage.