Artificial sweeteners permit people to keep their sugar and energy intakes down, yet still enjoy the delicious sweet tastes of their favorite foods and beverages. The Food and Drug Administration (FDA) has approved the use of four artificial sweeteners -saccharin, aspartame, acesulfame potassium (acesulfame-K) and' sucralose. Two others have petitioned the FDA and are awaiting approval - alitame and cyclamate. Saccharin, acesulfame-K and sucralose are not metabolized in the body; they pass through the kidneys unchanged. In contrast, the body digests aspartame as a protein. In fact, aspartame is technically classified as a nutritive sweetener because it yields energy, but for all practical purposes, that energy is negligible. Some consumers have challenged the safety of using artificial sweeteners. Considering that all compounds are toxic at some dose, it is hardly surprising that large doses of artificial sweeteners (or their components or metabolic by-products) have toxic effects. The question to ask is whether their ingestion is safe for human beings in quantities people normally use (and potentially abuse). The answer is yes, except in the case of aspartame, which may present a problem for certain people and so carries a warning on its label.