Background/aim: The objective of this study was to investigate and analyze the behavioral and neurochemical effects of monosodium glutamate (MSG) injections at various and subsequent dosages on male Wistar rats during the neonatal period. Materials and methods: In order to determine the behavioral and neurochemical effects of MSG, the experiment was implemented on neonatal male Wistar rats and the test was repeated for various MSG dosages. After completing the experiment, additionally, levels of dopamine, GABA, catecholamine (dopamine, noradrenaline, and adrenaline) and glutamate in the brain cells of the decapitated rats were also measured using the ELISA method. Results: Considering the results of the behavioral test, when we compared the test values of the control group with the values of the MSG-injected groups we noted that there were significant differences in the statistical figures obtained. Additionally, we found that the statistical figures of some neurochemical parameters were also significantly different when we compared the values of the MSG group with the control values. Conclusion: MSG injection has a clear effect on the neurochemical parameters, learning memory, and locomotor activities of rats.