Increasing numbers of neurotoxins or therapeutic agents that have specific target cells or receptors can be used to assess the developmental correlation between the structure and function of various organs including the brain. Patients with chronic diseases are now able to maintain their social activities but still must be medicated for a long period of their life. This might increase the potential hazard of prenatal drug exposure in the progeny. Functional teratology is quite a new concept in neuroscience. Recent observations of our laboratory and those of others suggest that the sensitive period for functional teratology might encompass the whole stage of fetal life in animals and humans. The shortage of precise information on the developmental integration of the structure and function of the neurons with different properties is a problem to be solved for the further progress of developmental pharmacology and toxicology. Single exposures to drugs at a different stage during the gestational period of rats or mice might provide more useful information on the relationship between the lesioned area and related functional disorders manifested postnatally. This paper reviews recent advances in developmental neuropharmacology and functional neuroteratology including beneficial points of the short-term exposures to drugs.