A cyclic oligomer of alpha-D-glucopyranose. The most common cyclodextrins are alpha, beta and gamma cyclodextrin having 6,7 and 8 glucopyranose units respectively. They occur naturally in starch digests of the bacteria Bacillus Macerans. With a hydrophobic interior cavity, they can complex small hydrophobic molecules while remaining soluble in water. Potential applications include water-soluble pharmaceuticals and herbicides and pesticides.