Death rate from unintentional poisoning, OWID

A poison can be any substance that is harmful to the body. It can be swallowed, inhaled, injected or absorbed through the skin. Poisoning is the harmful effect that occurs when too much of that substance has been taken. Poisoning is not to be confused with

envenomation Envenomation is the process by which venom is injected by the bite or sting of a venomous animal. Many kinds of animals, including mammals (e.g., the northern short-tailed shrew, ''Blarina brevicauda''), reptiles (e.g., the king cobra), spiders ...

. Acute poisoning is exposure to a poison on one occasion or during a short period of time. Symptoms develop in close relation to the degree of exposure. Absorption of a poison is necessary for systemic poisoning (that is, in the blood throughout the body). In contrast, substances that destroy tissue but do not absorb, such as

lye A lye is a metal hydroxide traditionally obtained by leaching wood ashes, or a strong alkali which is highly soluble in water producing caustic basic solutions. "Lye" most commonly refers to sodium hydroxide (NaOH), but historically has been u ...

, are classified as

corrosive A corrosive substance is one that will damage or destroy other substances with which it comes into contact by means of a chemical reaction. Etymology The word ''corrosive'' is derived from the Latin verb ''corrodere'', which means ''to gnaw'', ...

s rather than poisons. Furthermore, many common household medications are not labeled with

skull and crossbones A skull and crossbones is a symbol consisting of a human skull and two long bones crossed together under or behind the skull. The design originated in the Late Middle Ages as a symbol of death and especially as a ''memento mori'' on tombstones. ...

, although they can cause severe illness or even death. In the medical sense,

toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

and poisoning can be caused by less dangerous substances than those legally classified as a poison.

Toxicology Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating e ...

is the study and practice of the symptoms, mechanisms, diagnosis, and treatment of poisoning. Chronic poisoning is long-term repeated or continuous exposure to a poison where symptoms do not occur immediately or after each exposure. The patient gradually becomes ill, or becomes ill after a long latent period. Chronic poisoning most commonly occurs following exposure to poisons that

bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...

, or are biomagnified, such as mercury, gadolinium, and

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

. Contact or absorption of poisons can cause rapid death or impairment. Agents that act on the

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...

can paralyze in seconds or less, and include both biologically derived neurotoxins and so-called

nerve gas Nerve agents, sometimes also called nerve gases, are a class of organic chemicals that disrupt the mechanisms by which nerves transfer messages to organs. The disruption is caused by the blocking of acetylcholinesterase (AChE), an enzyme that ...

es, which may be synthesized for

warfare War is an intense armed conflict between states, governments, societies, or paramilitary groups such as mercenaries, insurgents, and militias. It is generally characterized by extreme violence, destruction, and mortality, using regul ...

or industry. Inhaled or ingested

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

, used as a method of

execution Capital punishment, also known as the death penalty, is the state-sanctioned practice of deliberately killing a person as a punishment for an actual or supposed crime, usually following an authorized, rule-governed process to conclude that ...

gas chamber A gas chamber is an apparatus for killing humans or other animals with gas, consisting of a sealed chamber into which a poisonous or asphyxiant gas is introduced. Poisonous agents used include hydrogen cyanide and carbon monoxide. History ...

s, almost instantly starves the body of energy by inhibiting the enzymes in mitochondria that make ATP. Intravenous injection of an unnaturally high concentration of potassium chloride, such as in the execution of prisoners in parts of the United States, quickly stops the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...

by eliminating the cell potential necessary for

muscle contraction Muscle contraction is the activation of tension-generating sites within muscle cells. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as ...

. Most biocides, including pesticides, are created to act as poisons to target organisms, although acute or less observable chronic poisoning can also occur in non-target organisms (

secondary poisoning Secondary poisoning, or relay toxicity, is the poisoning that results when one organism comes into contact with or ingests another organism that has poison in its system. It typically occurs when a predator eats an animal, such as a mouse, rat, o ...

), including the

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...

s who apply the biocides and other

beneficial organism In agriculture and gardening, a beneficial organism is any organism that benefits the growing process, including insects, arachnids, other animals, plants, bacteria, fungi, viruses, and nematodes. Benefits include pest control, pollination, and ...

s. For example, the herbicide 2,4-D imitates the action of a plant hormone, which makes its lethal toxicity specific to plants. Indeed, 2,4-D is not a poison, but classified as "harmful" (EU). Many substances regarded as poisons are toxic only indirectly, by

toxication Toxication, toxification or toxicity exaltation is the conversion of a chemical compound into a more toxic form in living organisms or in substrates such as soil or water. The conversion can be caused by enzymatic metabolism in the organisms, as w ...

. An example is "wood alcohol" or methanol, which is not poisonous itself, but is chemically converted to toxic

formaldehyde Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section ...

and formic acid in the

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...

. Many drug molecules are made toxic in the liver, and the genetic variability of certain liver

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

s makes the toxicity of many compounds differ between people. Exposure to radioactive substances can produce radiation poisoning, an unrelated phenomenon.

Treatment

If a person is suspected to have been exposed or ingested a poison, medical assistance to determine an appropriate treatment is necessary. If a suspected poisoning has occurred but the person is awake and alert, it is recommended to call the local poison information centre. If the person has collapsed or is having difficulty breathing, emergency medical assistance is required. To assist medical personnel, describe the person's symptoms, age, weight, other medications that person is taking, and any information about the poison. Try to determine the amount ingested and how long since the person was exposed to it. If possible, have on hand the pill bottle, medication package or other suspect container. The treatment will depend on the substance to which the patient is exposed. Depending on the type of poisoning, some first aid measures may help. Treatments include activated charcoal, induction of vomiting and dilution or neutralizing of the poison.

Prevention

Prevention strategies include locking up medicines and cleaners, reading labels on medicines and cleaners before using or storing, and safely discarding unneeded medicines, herbal supplements, and vitamins.

References

External links

{{Authority control Toxicology Poisons