In environmental medicine, we frequently see patients who have a very firm, sometimes fixated view of the nature of their disease, and they do not except the correction by the physician but only confirmation. Therefore, we face the task to undertake these patients a careful medical and psychological differential diagnosis. In a major number of cases, the symptoms are caused not by supported environmental effects but by an unknown diagnosis, and recognition and treatment would be impossible in case of an uncritical adoption of the patient's illness theory. Further, psychosomatic syndromes, which are well accessible by treatment procedures of psychosomatic medicine, can be diagnosed in many of those patients. This article demonstrates the different kinds of psychosomatic diseases in the area of environmental medicine and its appropriate therapeutic consequences.