The challenge of determining the health risks of low-dose chemical exposures

The challenge of determining the health risks of low-dose chemical exposures Rebecca J. Wilson and Pamela J. Lein, explore whether the dose makes the poison or not. Here, they discuss the challenges of determining health risks associated with low-dose chemical exposures. Nearly 500 years ago, Swiss physician and chemist Paracelsus originally expressed a fundamental tenet of toxicology: “All things are poison and nothing is without poison; only the dose makes a thing not a poison.” In other words, all substances are harmful at a high enough dose, but at low doses, the same substance is non-toxic or even therapeutic.