The author advocates preventive trials based on the hypothesis that psychosomatic diseases are caused by frustrations induced in some people during their communication with key figures in the family and work groups to which they belong. Certain people are more resistant to such psychosocial stresses by a higher degree of basic security which they owe partly to hereditary factors, partly to an education which was characterized by adequate consistent conditioning. Others, who have been less consistently conditioned are more prone, if frustrated, to develop neurotic or psychosomatic illness. Another important causative factor is the tendency, enforced by the customs of modern Western society, to inhibit the discharge of feelings of frustration in speech or action. The prevention of psychosomatic diseases should therefore be directed at: (a) improvement of education and personality formation in the family, the schools and the work group; (b) improvement of human communication in the family and work groups and in the society at large, and (c) recognition of precursors and early signs of psychosomatic disease, followed by combined medical and psychotherapeutic treatment as a form of secondary prevention.