Cholinesterase distribution in trigeminal ganglion was studied in rabbits by the thiocholine method. The presence of acetylcholinesterase conditions either a) a diffusive cytoplasmatic reaction of varying intensity — from very weak to very strong — or b) an unevenly intensively distributed reaction pronounced on the periphery of ganglion cells. — The histochemical localization of biogenic monoamines was studied with the aid of the fluorescent method according to Falck and Hillarp. Green-yellow varicose terminals were found in the neighbourhood of blood vessels, between myelinized fibres, and, finally, in close vicinity of ganglion cells with which they probably form synaptic contacts.