The food azo dyes are significant biologically active materials. Thermal behavior of disodium6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate, sunset yellow or E110 named (Figure 1), food dye was studied in correlation with the physical, chemical and biologically antioxidant properties [1]. Atomic transitions and atomic bonds behavior in molecules, fluorescent excitation of the compound has been identified by spectroscopic FTIR, UV-Vis, atomic fluorescence and Raman techniques. Optical properties were determined through refractive index for different concentrations measurements. Relative electrical permeability, electronic polarization and others were calculated. Biological of azo dye activity has been evidenced through their interaction with animal proteins and azo dye toxicity, to plants, it was manifested through the treatment of wheat with different concentrations azo dye solutions. Were measured surface tension and pH of the azo dye solutions depending on the temperature [2]. Figure 1 Figure 2 Thermal analysis measurements were performed in air dynamic atmosphere (150 cm3/min) at 10 K/min to 1000 °C, using alumina crucibles with PerkinElmer Diamond TG/DTA device [3]. These measurements of sunset yellow revealed a thermal stability till 350 °C (Figure 2). The visible absorption band with a peak at the wavelength 482.47 nm, for sunset yellow solution c = 0.0025 %, has absorbance value of 0.785. The study was conducted in order to determine the bioactivity behavior of sunset yellow.