d-Mannose is a simple sugar found naturally in fruits such as cranberries and pineapples. It is absorbed slowly from the gastrointestinal tract and unlike many sugars, it is not converted into glycogen or stored in the liver. Much of it is excreted in the urine, where it is thought to promote normal urinary health. Preliminary research indicates that d-mannose may help support proper urinary health by maintaining a healthy environment for the mucosal surfaces of the urinary tract. D-mannose is thought to play important roles by promoting the proper binding and flushing of bacteria from the urinary tract.