Results obtained with Kemadrin in the treatment of parkinsonism were compared to the effectiveness of Artane (alpha-cyclohexyl-alpha-phenyl-1-piperidinepropanol hydrochloride) and Pagitane. Patients (87) in the series received Kemadrin for periods of 3 to 20 months and were evaluated by a battery of our objective tests previously described. Kemadrin is procyclidine hydrochloride, and the structural formula differs only slightly from those of Artane and Pagitane. Kemadrin was gradually substituted into the patient''s therapy and in most cases a dose of 5 mg 3-4 times was well tolerated. In the series 38 patients were considerably improved with Kemadrin. Eighteen responded better to Artane and 11 patients improved more on Pagitane. Only 3 patients were adversely affected by Kemadrin. A discussion as to the difficulties of evaluating the therapeutic effectiveness of medication in parkinsonism was included.