Abstract: A fluorescent retrograde axonal tracer method for use in neuroanatomical studies of the brain involves the use of dilute solutions of amidino-stilbene compounds or salts, specifically 2-hydroxy-4,4'-diamidinostilbene isethionate. The amidino stilbene tracer exhibits a high sensitivity and fluorescent intensity, retrogradely fills axons and dendrites extensively, is highly resistant to fading, is compatible with virtually all other histochemical procedures, and exhibits minimal uptake by fibers of passage. The method of using amidino stilbene or stilbamadine compounds involves injection of a dilute solution of the compound into the area of the brain to be studied. After a period of time, the tissue is examined under a fluorescence microscope.