Glucomannan, which is classified as a soluble dietary fiber, is derived from konjac flour. Konjac flour itself is derived from the Amorphophallus species, plants which are related to the common philodendron house plant and which grow in only certain parts of the world, including some regions in China and Japan. One member of the Amorphophallus genus called Amorphophallus konjac, is also known as voodoo lilly, devil's tongue and konjac. Konjac flour, however is derived from the tubers of various species of Amorphophallus, and the term konjac is used generically for the various species, as well as for the flour from their tubers. In addition to being known as konjac, the plant is called ju ruo (pronounced in Chinese) by the Chinese people, and called konjaku or konnyaku by the Japanese.Konjac flour has a long history of use in both China and Japan as a food substance and as a folk remedy. Glucomannan products are widely used in Japan and China as general health aids, topically, for skin care and as a thickening agent for foods, among other things. Glucomannan, sometimes called konjac mannan, is marketed in the United States as a dietary supplement. Polysaccharides containing D-mannose and D-glucose in similar proportions to that found in konjac flour are found in other organisms, such as certain yeasts. Yeast glucomannan is not marketed as a dietary supplement.