Many papers documented that Parkinson's disease (PD) patients treated with levodopa (L-dopa) shows elevated plasma homocysteine (Hcy) levels. Several lifestyle factors are able to influence plasma Hcy levels. We review the evidence that L-dopa therapy is related with an increase in plasma Hcy levels and that several behaviours could be able to cause changes in plasma Hcy concentrations. Therefore, there are reasons to suggest that a healthy lifestyle lowering Hcy may prevent this potential iatrogenic complication during L-dopa therapy. Moreover, at present, no controlled prospective studies have evaluated this phenomenon.