Objective: To study the change of the blood level of CORT and expression of CRHmRNA in asthma-tic rats and the effects of Bushendingchuan Decoction(Cornu Cervi, Herba Cistanches, Radix Morindae Officinalis, Radix Rehmanniae Preparata, etc.) on them. Methods: The change of level in CORT was measured by radioimmunoassay, the change of level in hypothalamic CRHmRNA was measured by RT-PCR(Reverse transcription and polymerase chain reaction by the semi-quantitative determination). Results: The blood level of CORT decreased(P