In recent studies, disorders of chromatic and achromatic vision in parkinsonian patients have been demonstrated; these could be partially restored after application of L-Dopa. In this study, the effect of a 3-day infusion therapy with amantadine sulphate on color vision was evaluated in 19 parkinsonian patients by use of the Farnsworth-Munsell 100-Hue test. Under this treatment, the motor symptoms of parkinsonism improved significantly as assessed by the part "motor examination" of the Unified Parkinson's Disease Rating Scale (UPDRS). However, the total error scores of the Farnsworth-Munsell 100-Hue test before and after amantadine sulphate infusions were unchanged [before therapy, 94.53 (SD = 52.09); after therapy, 99.5 (SD = 58.81)]. From these results, it can be concluded that the pathophysiology of dopaminergic pathways in the visual system differs from that of the basal ganglia.