Determinations of biopterin (BP), homovanilic acid (HVA), glutamic acid (GTA), and glutamine (GT) levels in cerebrospinal fluid (CSF) obtained through a lumbar tap were performed in 20 parkinsonian patients in different stages of evolution and without medication. In patients with motor symptoms not related to Parkinson''s disease (dystonia, dyskinesia and essential tremor) (n = 4). In 7 other neurological patients subjected to spinal tap for diagnostic procedures neurotransmitters were also determined and taken as control groups.In 14 of the patients with Parkinson''s disease, the symptoms were evaluated using conventional scales (UPDS, NYPDS, NWPDS, Schwab and England, and Hoehn and Yarn-scale). The amplitude and the frequency of tremor were quantitatively evaluated through a single plane accelerometer Grass SP-1, akinesia was measured through reaction time to auditory stimuli, and rigidity through the speed of lineal movement. Evaluations were performed with the patient not on any medication for 1 week and repeated 1 h after the intake of 250 mg of 200/50 L-dopa/carbidopa preparation (Sinemet) and on a different day after the intake of biperiden (Akineton) 6 mg/day.