There is no universally accepted definition of a commonly used term for a functional food: nutraceutical. For the purposes of this article, a nutraceutical is any ingredient found in foods that has a demonstrated (or proposed) physiologic benefit. Although a nutraceutical is generally taken to be an ingredient that can be isolated or purified from food, plants, or marine products and made available in medicinal form, this article also considers claims of benefit to the urinary tract for foods or food supplements in which the active ingredient has not yet been characterized or isolated.