Chitosan.

Chitosan is a form of fiber that is found in chitin, the main material in the exoskeleton shells of crustaceans. In the late twentieth century, scientists began experimenting with chitosan as a possible medicine or dietary supplement. Most claims about chitosan relate to its uses when ingested into the digestive system. Like other forms of fiber, it is not digestible but may bind with fat and other potentially unhealthy materials and remove them from the body before they can be absorbed. Tests of this claim have been highly mixed. Some scientists and medical personnel recommend chitosan for other tasks, including cleaning the teeth, reducing inflammation, and improving the healing of damaged skin.