This International Standard specifies a high-performance liquid chromatographic (HPLC) method for the determination of the carbadox content in premixtures and animal feeding stuffs. The method is applicable to animal feeding stuffs with a mass fraction of carbadox of 0,5 mg/kg (limit of quantification) to 100 mg/kg, and to premixtures with a mass fraction of carbadox up to 10 %. The lower limit of detection is 0,1 mg/kg. NOTE 1 For animal feeding stuffs the mass fraction of carbadox is expressed in milligrams per kilogram, and for premixtures as a percentage by mass. NOTE 2 Carbadox is a chemotherapeuticum belonging to the quinoxaline group. Carbadox is used as a growth-promoting feed additive for piglets