Fogo selvagem presents our specialty with a unique situation. The disease is fundamentally identical to the pemphigus foliaceus that we are familiar with in North America, but there is impressive epidemiologic and circumstantial evidence that an environmental factor is producing this highly specific autoimmune phenomenon. If one can define this factor and investigate the mechanisms operative in the promotion of the disease, one would develop major new insights into both the normal function of the immune system and the specific disease state. Implications for understanding other autoimmune diseases are also obvious. However, to overcome the difficult logistics of studying these patients by modern techniques presents a formidable task. Hopefully, with the cooperation of interested investigators in both Brazil and the United States, these problems can be overcome.