beta-D-fructopyranose is the six-member ring form of fructose: a simple ketonic monosaccharide found in many plants and often bonded to glucose to form the disaccharide sucrose. It is the dominant structural isoform in crystalline fructose. In solution, fructose exists as a mixture of 70% fructopyranose and about 22% fructofuranose, as well as small amounts of three other forms, including the acyclic structure. Fructose can be used as a treatment for diabetic ketosis, acute alcohol intoxication, and phenylketonuria.