poison

Introduction
Nature of a toxic substance
- Definition of a poison
- Classification of a poison
  - Classification based on origin
  - Classification based on physical form
  - Classification based on chemical nature
  - Classification based on chemical activity
  - Other classifications
- Transport of chemicals through a cell membrane
- Conditions of exposure
  - Routes of exposure and absorption of chemicals
    - Injection
    - Ingestion
    - Topical (skin)
    - Inhalation
  - Frequency of exposure
  - Dose of exposure
- Distribution of toxicants in the body
  - Role of the lymphatics
  - Role of the blood
  - Role of tissue blood flow
  - Role of protein binding
  - Role of distribution barriers
- Elimination of toxicants
  - Excretion
  - Biotransformation
- Therapeutic, toxic, and lethal responses
  - Morphological versus functional toxic responses
  - Local versus systemic toxic responses
  - Immediate versus delayed toxic responses
  - Reversible versus irreversible toxic responses
  - Chemically induced immune responses
    - Cellular and humoral immunities
    - Allergies
- Teratogenesis
- Carcinogenesis
- Mutagenesis
Types of poison
- Agricultural and industrial chemicals
  - Agricultural chemicals
    - Insecticides
    - Herbicides
    - Rodenticides
    - Plant growth regulator
  - Industrial chemicals
    - Organic compounds
    - Inorganic compounds
  - General air pollutants
- Drugs and health care products
  - Painkillers
  - Tranquilizers and sleeping pills
  - Antipsychotic drugs
  - Cold medications
  - Antiseptics
  - Vitamins and iron pills
  - Antidepressants
  - Drugs of abuse
  - Cardiovascular drugs
  - Antiasthmatics
- Poisons of biological origin
  - Importance to humans
  - Microbial toxins
    - Moneran toxins
    - Mycotoxins
    - Protistan poisons
  - Plant poisons (phytotoxins)
  - Animal poisons (zootoxins)
- Radiation
  - Radiation, radioactivity, and radioisotopes
  - Ionizing radiation
    - Radiation sources
    - Adverse effects of ionizing radiation
    - Toxicities of whole-body ionizing radiation
    - Local toxicities of common beta-particle emitters
    - Local toxicities of common alpha-particle emitters
  - Nonionizing radiation
    - Ultraviolet radiation
    - Infrared radiation and microwaves
    - Lasers

References & Edit History Quick Facts & Related Topics

Images & Videos

Poisonous mushrooms

Learn why the presence of Theobromine molecule in chocolates is toxic to dogs

Blue-ringed octopus

Absorption, distribution, and excretion of toxicants

Toxicant accumulation in target organs

Ask an expert: What makes something poisonous?

Dose-response curve

How new beaver dams might damage the environment

Five structural diagrams of well-known alkaloids-morphine, quinine, ephedrine, strychnine, and nicotine-showing their organic nitrogen-containing base chemical structures, each labeled with its name.

At a Glance

fly agaric

poison: Media

biochemistry

Videos

Poisonous mushrooms

Poisonous mushrooms

More than 100 species of mushrooms are known to be poisonous to humans.

Video: © American Chemical Society (A Britannica Publishing Partner)

Learn why the presence of Theobromine molecule in chocolates is toxic to dogs

Learn why the presence of Theobromine molecule in chocolates is toxic to dogs

Why chocolate is bad for dogs.

Video: © American Chemical Society (A Britannica Publishing Partner)

Ask an expert: What makes something poisonous?

Ask an expert: What makes something poisonous?

Understanding the correlation between the type of poison and the amount required...

Video: © American Chemical Society (A Britannica Publishing Partner)

How new beaver dams might damage the environment

How new beaver dams might damage the environment

Learn about a toxic downside to restoration of beaver habitat: a temporary spike...

Video: © American Chemical Society (A Britannica Publishing Partner)

The Difference Between “Poisonous” and “Venomous”

The Difference Between “Poisonous” and “Venomous”

Bite or be bitten.

Video: Encyclopædia Britannica, Inc.

Images

Blue-ringed octopus

Blue-ringed octopus

The venomous blue-ringed octopus (genus Hapalochlaena) is small but deadly,...

© MikaelEriksson/iStock.com

Absorption, distribution, and excretion of toxicants

Absorption, distribution, and excretion of toxicants

Toxicants travel through the human body by routes of absorption, distribution, and...

Encyclopædia Britannica, Inc.

Toxicant accumulation in target organs

Toxicant accumulation in target organs

Organs targeted by toxicants become sites of accumulation during repetitive exposures.

Encyclopædia Britannica, Inc.

Dose-response curve

Dose-response curve

Figure 3: Dose–response curves.

Encyclopædia Britannica, Inc.

Ergot

Ergot

The fungal disease of cereal grasses known as ergot is caused by the fungus Claviceps...

Walter Dawn

Five structural diagrams of well-known alkaloids-morphine, quinine, ephedrine, strychnine, and nicotine-showing their organic nitrogen-containing base chemical structures, each labeled with its name.

Alkaloids

Chemical structures of the well-known alkaloids morphine, quinine, nicotine, strychnine,...

Encyclopædia Britannica, Inc.

Infographic titled Common characteristics of toxic animals shows a timber rattlesnake, strawberry poison dart frog, and monarch butterfly, with callouts noting stillness, loud noises or smells, and bright distinctive markings.

Common characteristics and warning signs of toxic animals

An educational graphic illustrating the common characteristics of toxic animals,...

© NTCo—iStock/Getty Images Plus; © Isselee/Dreamstime.com; © Willowpix—E+/Getty Images; Photo illustration: Encyclopædia Britannica, Inc.

Ionizing radiation injury from atomic bomb

Ionizing radiation injury from atomic bomb

Photograph of a woman's skin burned in the pattern of the kimono she was wearing...

National Archives and Records Administration/Department of Defense

fly agaric

fly agaric

The fly agaric (Amanita muscaria) is a poisonous fungus.

Sven Samelius

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