Parkinson's disease (PD) is a neurodegenerative disorder that leads to impairment of balance and coordination. Therapy for the disease is still under investigation. Withania somnifera (A-Extract), a herbal medicine, has been known for a spectrum of health-promoting effects including activation of immune, muscle and neuronal systems. Therefore effect of A-Extract in the mouse model of PD was examined. The midbrain and corpus striatum of PD mouse showed increased levels of superoxide dismutase, catalase and malondialdehyde; and reduced levels of glutathione and glutathione peroxidase compared to the control. Treatment with A-Extract 100mg/kg for 7 days significantly improved all these enzyme levels compared to A-Extract untreated PD mouse brain. In the PD mouse grooming, stride length, movement, rearing were found to be decreased compared to the control. In addition, narrow beam walk and foot slippery errors were increased. Treatment with A-Extract improved all these physiological abnormalities. These data suggests that A-Extract is a potential drug in treating oxidative damage and physiological abnormalities seen in the PD mouse, if documented also in patients with PD.