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  • Toxicology is the study of the adverse effects of xenobiotics on living systems.

  • Toxicology assimilates knowledge and techniques from biochemistry, biology, chemistry, genetics, mathematics, medicine, pharmacology, physiology, and physics.

  • Toxicology applies safety evaluation and risk assessment to the discipline.

The word toxicology is derived from the Latinized form of the Greek word toxicon, meaning “arrow poison.” Poison, as a noun, dates back to the Old French poison or puison, meaning, originally a drink, especially a medical drink, but later signifying more of a magical potion or poisonous drink. The commonly misused term toxin formally should be used to refer to toxic substances produced biologically. Other terms, toxicant, toxic agent, and toxic substance, could be used to delineate the broader category of substances that are toxic, regardless of origin. Xenobiotics is a term referring to substances, whether toxic or not, foreign to a given organism.


History is about the past; it is not the past. The past is passive, objective, all encompassing. History is active, subjective, and selective. The further back in time that we look, the more problematic it is for us to reach, in the present, conclusions about what happened in the past.

Science begins with observation. In the distant past, our observational skills did not extend beyond our senses in assessing toxicity and safety. Our hominin ancestors used the process of trial and error making careful note of which substances, particularly potential food sources, were safe and which were hazardous. Although it might very well be after the damage was done, they and their tribe and descendants would quickly learn to differentiate between the safe and toxic. Toxic substances were to be avoided, unless used against enemies.


Ancient China

Shen Nong, the legendary founder of Chinese Herbal Medicine, also known as the farmer god, and said to live circa 2800 B.C., was said to have tasted hundreds of herbs daily to differentiate the poisonous from the medicinal or just plain edible. He is considered the compiler of perhaps the world’s first pharmacological compendium, Divine Farmer’s Classic of Materia Medica.

Du (毒) is the standard word for poison or toxicity in Chinese. It was understood by the ancient Chinese that herbals were potentially toxic and dose played a role. Aconite, derived from the plant wolfsbane and possessing extreme potential toxicity, was widely used medicinally in small doses in China over 2000 years ago—usually applied externally to treat various wounds or ingested as a tonic to restore qi (the vital energy defined by Chinese medicine) and extend life. Unadulterated aconite in larger doses was often used to murder. Today we know that the alkaloids in aconite have a narrow therapeutic index and their use is not ...

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