Halquinol, a chlorinated derivative of 8-hydroxquinoline, is added to animal veeds for prevention of E. coli and Salmonella infections. It is composed of 57-74% 5, 7-Dichloro-8-quinolinol, 23-40% 5-Chloro-8-quinolinol, and up to 7-Chloro-8-quinolinol. It is used as Veterinary medicine and as a feed additive.