1-(3-Chloroprop-2-enyl)-3,5,7-triaza-1-azoniatricyclo[3.3.1.13,7]decane;chloride
Quaternium-15 is a quaternary ammonium salt used as a surfactant and preservative in many products including cosmetics. It is an anti-microbial agent by virtue of being a formaldehyde releaser, however this can also cause contact dermatitis, a symptom of an allergic reaction, especially in those with sensitive skin. In 2005, Quaternium-15 was named in the top 15 most frequently positive allergens identified in patch tests by the North American Contact Dermatitis Group (NACDG).  Sensitivity to Quaternium-15 may be identified with a clinical patch test.