Direct Congo Red is defined as a secondary diazo dye that give this a water soluble nature and yield a red colloidal solution. As compared to water, this dye shows good solubility in organic solvents mention as ethanol. Therefore, it has been used in dyeing material like cotton, flax, viscose rayon, jute and acetate. In addition, this is also used in testing procedure of hydrochloric acid in gastric content, hence helps in detecting amyloidosis.