Chitosan is a linear polysaccharide made from the deacetlyation of chitin, which is a compound found in the shells of crustaceans, insects and in fungi cell walls. Chitosan is used agriculturally as a seed treatment and a plant growth enhancer and as a biopesticide. It can be used in the water filtration process to cause fine sediments to bind together to aid in their removal by filtration from water, as well as to aid in the removal of phosphorus, heavy minerals and oils. In medicine, it has been used to help blood to clot rapidly. It has unsupported medical claims that it can attract fat from the digestive system and aid in its expulsion before it is absorbed, leading to weight loss. These claims have never been proven at this time.