Background and Aim: The use of food dyes can cause certain diseases, such as anemia and indigestion, along with other disorders, tumors, and even cancer. Therefore, this study aimed to determine the chemical nature and toxicity of some commercial dyes locally used in processed foods compared with standard food dyes. Materials and Methods: Three types of standard and commercial food color additives (Sunset Yellow, Tartrazine, and Carmoisine) were extensively examined. The chemical structures and functional groups of the dyes were evaluated by Fourier-transform infrared (FTIR) spectroscopy. The melting temperatures of the dyes were also determined by chemical thermal analysis. The acute toxicity test to evaluate the standard and commercial food color safety was estimated by a range-finding study using 150 Wistar albino rats. Sub-groups were administered one of the three colors under study at doses of 2, 3, 4, and 5 g/kg body weight (BW) orally for 7 days. When no mortality was observed, an additional 15 g/kg BW was administered. Concerning the median lethal dose 50 (LD50), 38 rats were exploited using the up-and-down method. Results: Commercial dyes had lower melting points than standard colors. Regarding the range-finding study, rats receiving different doses of the dyes exhibited no signs of toxicity, no deaths, and no clinical or gross pathological signs throughout the 7 days of the experiment. However, the animals that were dosed with 15 g/kg BW of each dye showed signs of loss of appetite, tachycardia, drowsiness, and eventual death. The LD50 values of the commercial food dyes, particularly Sunset Yellow and Carmoisine, were lower than those of the standard dyes. Conclusion: Commercial food colors were more toxic to rats than standard food colors. Differences were observed between the purity of the standard and commercial dyes, and the latter ones contained different percentages of salt, indicating the occurrence of fraud in commercial markets. Keywords: acute toxicity, food colors, Fourier-transform infrared spectroscopy, lethal dose 50, range-finding study.
