Three mechanisms for disease caused by mold—infection, allergy, and toxicity—are established and well recognized by clinicians. In each case the corresponding diseases are specific to a particular fungus. The mechanisms involved include a recognized inflammatory pathology that leads to objective clinical evidence of disease. Recent widespread litigation has arisen out of an unproved assertion that exposure to indoor molds causes an ill-defined illness. This illness is characterized by the absence of objective evidence of disease and by the lack of a defined pathology. There is usually no specificity for the involved fungus purported to cause the illness. Those publications that claim such an illness are reviewed. They are found to lack scientific validity, often on the basis of faulty methodology and insufficient information. There is no coherent clinical description for the presumed illness. Recommendations are offered for published reports and studies to address this problem.