Terguride, a partial DA-agonist with both dopaminergic and antidopaminergic properties, was tested in 11 PD patients in the "decompensated" phase of the disease, characterized by the presence of dyskinesias and motor fluctuations. Combined treatment of these patients with 1 mg/day of terguride and stabilized doses of levodopa reduced the severity and frequency of dyskinesias and motor fluctuations along with a slight but significant improvement of parkinsonian clinical picture. The "modulatory" effect of terguride on DA receptors, in this experimental conditions, is discussed.