Relgin 0.5 Tablet is used alone or in combination with another medication to treat the symptoms of Parkinson's disease. Parkinson's disease is a condition in which regions of the brain gradually weaken over time. Parkinson's disease symptoms include involuntary shaking of certain body parts (tremors), sluggish movement, and stiff and inflexible muscles. In Parkinson's patients, there is a decrease in dopamine (a chemical messenger that is important for movement control) levels as the nerve cells that produce dopamine begin to die.