5-Sulfosalicylic acid is a derivative of salicylic acid, a common anti-inflammatory drug. Sulfosalicylic acid is used in urine tests to determine urine protein content. The chemical causes the precipitation of dissolved proteins, which is measured from the degree of turbidity. It is also used for integral colour anodizing. 5-Sulfosalicylic acid dihydrate is a poly functional metal chelating ligand that may be used to form metal coordination complexes. Spray reagent for the detection of amino acids on TLC plates. Doping agent for polyaniline.