Mazindol, a drug that blocks the reuptake of dopamine, was studied in the treatment of Parkinson's disease in both a pilot study (12 patients) and a controlled trial (11 patients). The patients had stage II or III disease, according to the classification of Hoehn and Yahr. Both studies showed that mazindol possessed anti-parkinsonian properties and that the improvement was statistically significant. The therapeutic effect was moderate, but could be of value for patients in the early stages of the disease. The drug was well tolerated; only two patients had side effects.