Psychotropic drugs are discussed under the descriptive categories of antipsychotic, antidepressive, antimanic, anti-anxiety, and cognitive acting. In the antipsychotic classification, special attention is given to side effects (extrapyramidal motor signs, tardive dyskinesias, akathisis) and to dosage for the elderly. The section on congenitive acting drugs includes some pertinent observations on cognitive ability in the aging, the importance of correct diagnosis, and therapeutic strategy. The aged are a population at risk for not only disease, but iatrongenic illness due to direct and indirect drug action. Rational therapy involves understanding the underlying dynamics of the disease and thus the selection of the most effective treatment. Psychotropic drugs in an appropriate program are valuable therapeutic assets.