The aim of the paper was to trace the haloperidol effect in the acute and chronic experiments on the histofluorescence in the caudate nucleus of the rat and in conditions of pretreatment of those animals with agonistic and antagonistic compounds of acetylcholine. The experiments were performed on 35 Wistar rats of 180 g mean body weight. According to the experimental model the following were administered: alpha-MT; alpha-MT + haloperidol; Haloperidol in single dose and in repeated multiple doses; Atropine: Atropine + haloperidol; carbachol and carbachol + haloperidol. The Falck et al.  histofluorescence method was applied to demonstrate catecholaminergic structures. Changes in the fluorescence of nucleus caudatus of the rat after single or repeated administration of haloperidol and after combinations with cholinergic compounds were always accompanied by the decrease of histofluorescence. We assume that it can be accounted for the existence of functional bonds between the dopaminergic and the cholinergic systems. Those bonds can be explained on the structural grounds, that is by a dense network of nerve endings and in bundles of preterminal nerve fibres. Neurocytes bodies were not sensitive to the administered drugs. The dense network of nerve endings proved to be most sensitive to the action of haloperidol given by itself and in combination with other drugs. A single large dose of haloperidol produced more pronounced effects than several repeated doses of that neuroleptic.