Definition of Toxicity

Toxicity: The degree to which a substance can harm humans or animals.

Toxicity can be acute, subchronic, or chronic:

• Acute toxicity involves harmful effects in an organism through a single or short-term exposure.
• Subchronic toxicity is the ability of a toxic substance to cause effects for more than one year but less than the lifetime of the exposed organism.
• Chronic toxicity is the ability of a substance or mixture of substances to cause harmful effects over an extended period, usually upon repeated or continuous exposure, sometimes lasting for the entire life of the exposed organism.

See also: Radiation toxicity.