Introduction

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book introduces historical highlights and basic principles of toxicology. Toxicology is the study of interactions between chemicals or drugs, and biological systems. Humans, mammals, and environmental entities on the planet are increasingly exposed to chemicals of an enormous variety. Prehistoric humans were aware that liquids extracted from animals and plants contained natural poisons which were used on their weapons. In the Middle Ages, the art of poisoning for political ends developed into a cult. In the ancient Italian republics, the Borgias were infamous during the fifteenth and sixteenth centuries. Toxic substances are classified according to their use or exposure: pharmaceutical agents, food additives, pesticides, herbicides, occupational chemicals, environmental pollutants, naturally occurring toxins, and commercially available chemical products. Food additives are xenobiotic substances usually of low biological activity which are also ingested.