This study examined the effects of a protein rich diet on coping neurotransmitter levels in orally administered ampicillin–induced neurotoxic rats compared with propionic acid (PA) models of autism. 40 young male western albino rats were divided into four groups. The first group served as control and received phosphate buffered saline orally; the second group serving as autistic model was treated with oral dose of PA (250 mg/kg body weight/day for 3 days); the third group was treated with the neurotoxic dose of ampicillin (50 mg/kg for three weeks); the fourth group received the same dose of ampicillin and was fed with special protein rich diets. Noradrenaline, dopamine, serotonin glutamate, glutamine and interleukin 6 (IL-6) were measured in the brain homogenate of all tested groups. Specified doses of PA and ampicillin significantly (P<0.001) decreased noradrenaline, dopamine, and serotonin levels when compared to control. Also glutamate, IL-6 levels were significantly (P<0.001) increased in PA treated group while non-significant increase was found in ampicillin treated group. Non-significant increase of glutamine was found in PA treated group with a significant increase in ampicillin treated group. The effects of ampicillin on these parameters were found to be potentiated when the rats were fed on a protein rich diet. Our results end with the conclusion that dietary protein level may be a useful tool to find out a path to restrict neurotransmitter alterations in neurodevelopmental disorders like autism.