ABSTRACT
Toxicology is the scientific study of adverse effects of chemicals on living organisms. This science recognizes that chemical substances can be either beneficial or deleterious to a living organism. Paracelsus first articulated this relationship in the 15th-century:
All substances are poisons; there is none which is not a poison. The right dose differentiates a poison from a remedy
.
Beneficial effects of chemicals include providing energy, nutrients, and protection to the organism. Adverse effects, however, can occur if the chemical concentration adversely influences how cells, tissues, and organisms function. The degree of harm or the influencing factors of toxicity are related to:
