Background & Aim: Parkinson's disease (PD) can be created with loss of dopaminergic substantial nigra neurons which is widely associated with oxidative stress and reduced glutathione (GSH), as the most important and abundant thiol in tissues and one of the antioxidant defense, is one of the earliest biochemical events related to Parkinson's and consumption of antioxidants has a protective effect. In the present study, effect of ellagic acid on the rate of thiol groups has been studied within the hippocampus, striatum, cortex and cerebellum tissues in Parkinson's disease. Experimental: In this study were used 40 adult male rats that were divided randomly into eight groups: control, Parkinson's, and three Parkinson groups that once daily for 14 days received the gavage from doses 10, 25, and 50 mg/kg of ellagic acid. Parkinson's disease was induced with injection of 8 µg of 6_ hydroxy dopamine (6-OHDA) nerve toxin in 2 ml of saline containing 1% ascorbic acid in the middle-anterior bundle (MFB) of the left cerebral hemisphere of rats. After 14 days all rat brain were collected for the isolation and measurement of tissue thiol. Results & Discussion: In the PD group, in the all tissues observed a significant decrease in the thiol levels than the control group and administered ellagic acid in particular, 25 and 50 mg/kg was able to induce the effect of increase in the all tissues. This increase was significant in all tissues except cerebellum than PD group. Recommended applications/industries: Ellagic acid with having the ability to increase thiol can be used for treating and preventing progression of Parkinson's disease that created by oxidative stress. Manuscript profile