Hyperhomocysteinemia is as a risk factor for increased vascular disease in L-dopa-treated Parkinson disease (PD) patients. This effect Of L-dopa is associated with the metabolism Of L-dopa by methylation. This study aimed to assess the effect of pergolide on plasma homocysteine levels. Plasma homocysteine levels were compared between PD patients treated with pergolide as monotherapy, with L-dopa as monotherapy, or with an L-dopa and pergolide combination and compared with controls. Plasma homocysteine levels were significantly higher in the L-dopa monotherapy group, and there were no significant differences for the pergolide treatment groups. Pergolide can be beneficial for increased plasma homocysteine levels.