In asthma the bronchial muscle is hyperirritable, making asthmatics susceptible to a wide variety of external and endogenous trigger factors normally experienced by us all. The level of hyperirritability determines the risk of developing bronchospasm on exposure to the trigger factors. Bronchial muscle tone is in part maintained by vagal nerves. Emotional factors can act as triggers for bronchospasm through these nerves, particularly in patients with the greatest hyperirritability. Asthma itself may arouse hostilities in parents, peers, and therapists. By definition asthma can therefore be considered psychosomatic, but because of current usage, this term does not help good medical management. The complex interplay between the organic abnormality in asthma and the psychosocial environment should always be carefully considered.