A history of North American and European experience with biological toilets is provided. The early use of these devices in Scandanavia was to solve a specific problem, that of providing a low-cost solution for disposing of human wastes from recreational cabins. Because of their environmental attractiveness their popularity increased rapidly and their marketing area was widened to include year-round use. The same factors resulted in closer scrutiny by both Scandanavian and American agencies in the form of controlled and field testing programs. The results of these tests have been improved designs and understanding of the viable applications of the devices, which are significantly more limited than first implied.