Food additives while attract consumers, improve quality, control weight and replace sugar, may affect seriously children and adults health. Here, we investigated the adverse effects of saccharin and methylsalicyltaes as sweetener and flavoring agent on lipid profile, blood glucose, renal, hepatic function and oxidative stress/antioxidants (lipid peroxidation, catalase and reduced glutathione in liver tissues). Saccharin and methylsalicylate were administered orally in young male albino rats at low and high dose for 30 days. Rats were divided into 5 groups, 1st control group, 2nd and 3rd (low and high saccharin-treated groups) and 4th and 5th (low and high methylsalicylate-treated group). Serum total cholesterol, triglyceride, glucose levels and body weight gain were found decreased in saccharin high dose group compared to control. Rats consumed high dose of saccharin showed a significant decrease in serum triglycerides, cholesterol and LDL levels. Low and high doses of saccharin exhibited a significant increase in liver function marker of ALT, AST, ALP activity, total proteins and albumin levels and renal function test (urea and creatinine levels) in comparison with control group. Further, saccharin at high dose induced significant decrease in liver GSH levels, catalase and SOD activity and increase in hepatic MDA level. Overall saccharin harmfully altered biochemical markers in liver and kidney at higher as well as lower doses. Whereas, methyl salicylates did not pose a risk for renal function and hepatic oxidative markers.