¹Department of Pharmacy, Noakhali Science and Technology University, Noakhali-3814, Bangladesh DOI : 10.12991/marupj.319304 Now-a-days synthetic food dyes are being used most commonly as food colorant in confectionaries, drugs and cosmetics. Present study was designed to evaluate the toxic effect of tartrazine, a widely used azo dye, on Swiss Albino mice. Experimental animals were treated with tested dye at a dose level 200mg/kg & 400mg/kg body weight along with normal diet. Various physiological and biochemical parameters were assessed to study the toxic effect of tartrazine. Our study revealed a highly noticeable decrease in the body weight gain of mice at 400mg/kg dose compared with the control group. A significant variation in the average weight of the major organs (heart, kidney and liver) was also observed. The average weights of the heart and kidney were increased whereas the average weight of liver was decreased significantly. Serum triglyceride, creatinine and bilirubin levels were significantly increased, in contrast cholesterol level was decreased in the groups of mice treated with tartrazine. Keywords : Azo-Dye, tartrazine, Swiss Albino Mice, Physiological changes, Serum biochemistry