Although atopic dermatitis can be treated efficiently, there is still much controversy about the risk/benefit ratio of both topical corticosteroids and topical immunomodulators. Conflicting data may be found about the usefulness of bathing, diet regulation, and other therapeutic interventions. These controversies result in part from the persistence of Hippocratic doctrines in modern medical thinking. Humoralist and diathetic doctrines, as they pertain to eczema, are reviewed. The paradoxical worsening of oozing and the deadly hazards of hospitalization before the era of antibiotics are brought to mind. We hope that this historical review will improve the understanding of current controversies and help dermatologists to manage patients with atopic dermatitis and other chronic skin diseases.