Dicarboxylic acids are organic compounds that contain two functional carboxylic acid (–COOH) groups. Industrially, they are important in production of polyester, polyols, polyamides, and nylon and as a precursor to active pharmaceutical ingredients and additives. Dicarboxylic acids are important water-soluble components of atmospheric aerosols. Succinic, adipic, and glutaric acid may be harmful if inhaled, swallowed, or absorbed through skin. All these acids alone or in combination do not show any mutagenic effect. Some of the dicarboxylic acids (sebacic acid) have been advocated to have anti-hyperglycemic effect, whereas analysis of serum free fatty acids from patients with Reye's syndrome (acute encephalopathy with visceral steatosis syndrome) had revealed the presence of dicarboxylic acids in over half of the patients' total free fatty acids; both medium-chain (6–12 carbon lengths) and long-chain (14–18 carbon lengths) dicarboxylic acids were identified in such studies. Malathion, a well-known organophosphate pesticide, was previously marketed as Malathion dicarboxylic acid, is fetotoxic and toxic to infants and children.