text: The initial use of racemic dopa for the treatment of Parkinson's disease resulted in a number of adverse effects viz. nausea, vomiting, anorexia, involuntary movements and granulocytopenia. The use of L-dopa [the (S)-enantiomer] resulted in reducing the required dose, and adverse effects. The granulocytopenia was not observed with the single enantiomer.