Background: food additives are added to most junk and fast foods, especially those for kids. Sodium nitrite is an inorganic salt with widespread applications in the food industry as a color fixative and preservative in meat and fish. Annatto extract is a natural food color obtained from the outer coatings of the seeds of the Annatto tree (Bixa orellana L.). Monosodium glutamate (MSG), the sodium salt of amino acid glutamate, is a food additive that popularly used all over the world as “flavor enhancer". Aim of the work: this study was aimed to determine the hazardous effects of sodium nitrite, annatto and monosodium glutamate on some physiological parameters in male albino rats. Materials and methods: this studyhad been done on fourty male albino rats with an average body weight 100-145 g. The animals were divided into four groups; Group 1: control (untreated group), Group 2: sodium nitrite treated group < strong>, Group 3: annatto treated group and Group 4: monosodium glutamate treated group. Blood samples were collected, sera were separated and used for estimation of some biochemical parameters (liver enzymes, kidney functions, glucose, protein profile and lipid profile) and hormonal levels [testosterone, T3 (triiodothyronine) and T4 (thyroxine)]. Results: the biochemical results showed an increase in the activities of liver enzymes [aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT)], and the levels of glucose, kidney functions (urea, and creatinine), lipid profile [total cholesterol, triglycerides, low density lipoprotein (LDL-C)] and thyroid hormones [thyroxin (T4) and triiodothyronine (T3)] in all treated groups when compared to the control group. A drop in protein profile (total protein, albumin, globulin and A/G ratio), testosterone hormone and HDL level were observed in the treated groups as compared to the control rats. Conclusion: it could be concluded that some food additives like sodium nitrite, annatto, and monosodium glutamate have extreme effects on liver and kidney functions, protein and lipid profiles and also on thyroid and testosterone hormones. So, it is recommended to minimize the use of these additives to protect young children and mature people from these destructive effects.