ABSTRACT
Desired effect and toxic effect, when used to describe the end results of the interaction of a drug and a biologic system, are relative terms. They take on real meaning only within the context of the circumstances under which the chemical-biologic reaction occurs. Certainly, desired effect indicates that the purpose for which a drug is being used has been achieved. And toxic effect always means that a harmful effect has been produced on some biologic mechanism. Yet the two terms are occasionally synonymous, as for example when the action of a pesticide like malathion saves a farmer’s crop by eliminating a plant-destroying insect. This same effect would be considered very undesirable from another standpoint were the farmer accidentally exposed to quantities sufficient to make him ill or cause his death.
