toxicity

noun

tox·​ic·​i·​ty täk-ˈsi-sə-tē 

plural toxicities

: the quality or state of being toxic: such as

a

: the quality, state, or relative degree of being poisonous

measuring the toxicity level of the soil

The toxicity of some chemical agents degrades significantly over time, so it is unclear how lethal the stockpiles are.

—David S. Cloud

Administering a cocktail of drugs would dilute the toxicities of the different drugs and minimize the development of viral resistance to them.

—Rudy M. Baum and Ron Dagani

b

: an extremely harsh, malicious, or harmful quality

In the past few days, I've tuned in to C-SPAN to watch a number of the televised Senate debates, which illustrate all too vividly the toxicity of an uncivil tongue.

—Connie Schultz

In much of the ensuing commentary, court watchers worried that the justices' soaring rates of written dissents, nasty and personal attacks and scathing remarks read aloud from the bench bespeak a new toxicity in Supreme Court discourse.

—Dahlia Lithwick

Did you know?

Toxicity is often a relative thing; in the words of a famous old saying, "The dose makes the poison". Thus, it's possible to die from drinking too much water, and lives have been saved by tiny doses of arsenic. Even though botulinum toxin is the most toxic substance known, it's the basic ingredient in Botox, which is injected into the face to get rid of wrinkles. With some poisons, mere skin contact can be lethal; others are lethal when breathed into the lungs in microscopic amounts. To determine if a chemical will be officially called a poison, researchers often use the "LD50" test: If 50 milligrams of the substance for every kilogram of an animal's body weight results in the death of 50% of test animals, the chemical is a poison. But there are problems with such tests, and toxicity remains a very individual concept.

Examples of toxicity in a Sentence

Recent Examples on the Web

She was also treated for rodenticide toxicity, which occurs when humans or nontarget animals ingest rat or mouse poisons; however, caregivers did not believe that was the primary cause of her illness. — Saman Shafiq, USA Today, 12 Aug. 2026

After a forensic autopsy, the Mercer County coroner determined that the boy's cause of death was cocaine toxicity and the manner of death was ruled a homicide. — Madeline Bartos, CBS News, 11 Aug. 2026

Radiopharma’s precision promise runs into toxicity problems, China puts new guardrails around its biotech innovation engine, and Grail’s Galleri heads to an FDA advisory panel. — Meghana Keshavan, STAT, 10 Aug. 2026

Inland taipan Often described as the world’s most venomous snake based on laboratory toxicity tests, the inland taipan possesses venom capable of attacking the nervous system, muscles, and blood. — Atharva Gosavi, Interesting Engineering, 6 Aug. 2026

Word History

First Known Use

1873, in the meaning defined above

Rhymes for toxicity

• basicity
• chronicity
• complicity
• cyclicity
• duplicity
• ethnicity
• facticity
• felicity
• helicity
• plasticity
• publicity
• rusticity

Medical Definition

toxicity

noun

tox·​ic·​i·​ty täk-ˈsis-ət-ē 

plural toxicities

: the quality, state, or relative degree of being toxic or poisonous