Objective: This study was conducted to determine the behavioral disorders and neuroinflammation that occur in the rat model of autism. Materials and methods: A total of 25 rats, 20 of which were working and 5 were control group, were used in the study. The scores of the rats were recorded by performing a behavioral test before and after the application. A single dose of propionic acid (4 µl, 0.26 M solution) and (4 µl) saline were administered to the brain right ventricles of the rats in the working group and control group, respectively. Hippocampus tissue was obtained after the sacrification process on the 21st day of the rats and examined. Results: Dystrophic changes with small, pycnotic and hyperchromatic nuclei of neurons in the cerebral cortex and hippocampal region were detected in histopathological studies. It was determined that the primitive cell layer thickness of the working group decreased significantly, and their density increased due to irregular chromatolysis in neurons and abnormal Nissl granule distribution. It was determined that the number of glial fibrillar acid protein positive cells increased significantly in the cerebral cortex and hippocampal region in propionic acid applied rats. Conclusion: Propionic acid crosses the blood brain barrier. As a result, neuroinflammation, microglial activation and loss of myelin are observed in the brain.