In the present study, patients with asthma ware evaluated in order to find out if the emotional stress itself causes their asthmatic attack or not, and to elucidate the mechanisms underlining it. 41.8% of the 55 patients demonstrated asthmatic attack during hypnosis evaluated their symptoms and significant decrease in their air flow. The non-responders showed significant increase ind the serum DBH level (p < 0.05) during the hypnosis compared with their baseline value, while the responders did not show any significant change in the serum concentration. However, the responders shows significant increase in serum histamine concentration during (p < 0.01) and 40 min (p < 0.05) after the hypnosis. These data suggest that the increased sympathetic nerve activity during the hypnosis suppresses the release of chemical mediators from inflammatory cells and autonomic nerve terminals in the airways.