Compositions, methods, systems, etc., are provided for modified and/or purified fucans and corresponding fucan-containing compositions that inhibit fibrous adhesions among other advantages. The purified/modified fucans and fucan compositions have a reduced level of non- fucan components or impurities such as those found in a starting fucan composition. Such reduced undesirable components or impurities include, for example, undesired components bound to the fucan and compounds in the composition that are not a part of or bound to the fucan.本發明提供用於除其他優點外還抑制纖維性粘連之經修改及/或經純化聚海藻糖及含對應聚海藻糖組成物的組成物、方法、系統等。該等經純化/經修改聚海藻糖及聚海藻糖組成物具有減小量的非聚海藻糖組分或雜質,諸如該等於起始聚海藻糖組成物中發現者。此類減少的非所需組分或雜質包括例如結合於該聚海藻糖之非所需組分及並非該聚海藻糖之部分或未結合於該聚海藻糖之該組成物中之化合物。