Citric acid is a weak organic acid commonly used in the food, cosmetic and pharmaceutical industries.

The parent base of citric acid, citrate, is a component of the Krebs cycle and occurs naturally during metabolism in all living organisms. It is found naturally in citrus fruit such as lemons and limes and is used as a natural preservative.

Anhydrous citric acid has had the water molecules removed and is usually in a dry, powdered formulation.

Citrate or citric acid is often used to adjust pH, to add sour flavor to foods and beverages, and to form the salt derivative of minerals and metals for pharmaceuticals, as in the case of potassium citrate, a dietary supplement.