What is there that is not poison? All things are poison and nothing is without poison. Solely, the dose determines that a thing is not a poison.
Paracelsus History of dose response, J Toxicol Sci., 2010
The dose-response assessment or toxicity assessment provides a means of understanding whether human exposure to environmental contaminants has the potential to produce adverse health effects. The difference between doseresponse assessment and HI is that dose-response assessment is the process of quantifying (rather than identifying as merely possible) the relationship between the dose of a particular chemical to which an individual or population is exposed and the likelihood of adverse health effects.1