4-p-Chlorophenyl-1-(3-p-fluorobenzoylpropyl)-4-hydroxypiperidine (R.1625, Haloperidol) is a new compound synthesized by Janssen et al. (1959) and reported to have biological properties similar to those of the phenothiazines at a much lower dosage level. One difference, however, was a greater tendency to potentiate pentobarbitone hypnosis. Von Eiff and Jesdinsky (1960) conducted a “double blind” trial in 28 normal subjects using 4 mg. Haloperidol 2½ or 4½ hours before the experimental period. Subjective effects included fatigue or fatigue and agitation in females. The drug did not appear to influence intellectual function as tested, but reduced self-criticism. There were minor cardio-vascular effects and a tendency to fatigue in ergometry performances. A number of clinical reports have appeared (Divry et al., 1960; Delay et al., 1960) suggesting that Haloperidol is of value in psychomotor agitation and especially in mania in doses of 2–15 mg. daily. Gerle (1960) reports favourably on the drug in schizophrenic patients. Most authors note a high incidence of pseudo-Parkinsonian side-effects (40–80 per cent. of cases) and a section of a recent symposium on the drug in Belgium was devoted to “neurodysleptic syndromes” (dystonic reactions, oculogyric crises, etc.) produced by it. Pichot (1960) at the symposium reported that these reactions can be controlled by chlorpromazine.