Gluconolactone, a lactone of D-glucuronic acid, is a food additive with the E number E575. Gluconolactone is commonly found in honey, fruit juices, wine. In medcine, gluconolactone is used as a component of irrigation solution Renacidin for dissolution of bladder calculi of the struvite or apatite variety, and to prevent or minimize encrustations of indwelling urinary tract catheters.