There is provided a pharmaceutical composition comprising a therapeutically effective amount of R(+) pramipexole and a therapeutically effective amount of S(-) pramipexole, wherein said therapeutically effective amount of R(+) pramipexole is 50 milligrams plus or minus 10% to 5,000 milligrams plus or minus 10% and wherein said therapeutically effective amount of S(-) pramipexole is 0.125 milligrams plus or minus 10% to 4.5 milligrams plus or minus 10%, and therapeutically effective amounts of R (+) and S(-) pramipexole for use in the treatment or prevention of Parkinsons disease or the symptoms thereof.