The methodological problems connected with an anatomo-pharmacological study of nervous cells are examined here, in order to precise the chemical nature of these cells and their anatomical connections. The recent progress of retrograde axonal transport methods and the new histochemical techniques for the study of neurotransmitters allow to foresee many opportunities in this field. Consideration is given to anatomical and pharmacological methods, examined separately from one another; a possible combined study of them is also analyzed, taking into account the experimental results mentioned in literature.