Monosodium glutamate (MSG) is one of the commonest food additives in the developed world and it is commonly used as a flavor enhancer. MSG can be found in various concentrations in numerous food products. It is the salt of glutamic acid, one of the naturally occurring amino acids. Aim of work: the present review was prepared to illustrate the effects of Monosodium Glutamate on different vital tissues like pulmonary tissues, brain, liver, kidney, testes, and others.  Monosodium glutamate treatment showed numerous pathological changes in different vital tissues like the lung, including highly congested blood vessels, granuloma, ruptured bronchial walls, narrowed alveolar sacs, fibrosis, and increased collagen fibers which might induce oxidative stress Also, Monosodium glutamate treated rats showed decreased DNA content and increased protein content, increased amyloid–β protein content and increased PAS +ve materials in different tissues. Conclusion: the present study concluded that monosodium glutamate consumption led to numerous dystrophic changes in different tissues which might induce oxidative stress Therefore, MSG is considered a toxic agent due to increased production of ROS, so that, the ingestion of this substance by humans should be reviewed and great attention must be directed towards this substance to avoid its highly desirable uses.