The main uses of azo compounds are as dyes, food colourings and chemical indicators. Azo compounds are used in industry as dyes for many different textile types. These types of textile include silk, leather, wool and cotton which are namely intended for clothing and decoration. Azo colours come in different forms which include amido-azo, oxy-azo, diazo, tetrazo and other polyazo compounds. Many azo dyes have been prohibited in the EU due to their carcinogenic properties. The reason that azo compounds form different colours can be seen in the conjugation and colour section.
Direct colours such as direct blue 54 and congo corinth, a violet compound, dye cotton 'directly' without aid. Acid colours are used to dye animal fibres such as wool and silk in an acid bath. Examples include tartrazine, a yellow compound, and Bismark Brown. Bismark brown is also used as a food colouring in kippers.