Methylchloroisothiazolinone (MCI)

Methylchloroisothiazolinone is a preservative with antibacterial and antifungal effects within the group of isothiazolinones. It is effective against gram-positive and gram-negative bacteria, yeast, and fungi. Methylchloroisothiazolinone is found in many water-based personal care products and cosmetics. Methylchloroisothiazolinone was first used in cosmetics in the 1970s. It is also used in glue production, detergents, paints, fuels, and other industrial processes. Methylchloroisothiazolinone is known by the registered tradename Kathon CG when used in combination with methylisothiazolinone. Methylchloroisothiazolinone may be used in combination with other preservatives including ethylparaben, benzalkonium chloride, or 2-bromo-2-nitropropane-1,3-diol. Methylchloroisothiazolinone is an allergen for a small but growing portion of individuals.