
A
poison
Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...
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.
Acute poisoning is exposure to a
poison
Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...
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, are classified as
corrosives rather than poisons. Furthermore, many common household medications are not labeled with
skull and crossbones, although they can cause severe illness or even death. In the medical sense,
toxicity and poisoning can be caused by less dangerous substances than those legally classified as a poison.
Toxicology 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, or are
biomagnified, such as
mercury
Mercury commonly refers to:
* Mercury (planet), the nearest planet to the Sun
* Mercury (element), a metallic chemical element with the symbol Hg
* Mercury (mythology), a Roman god
Mercury or The Mercury may also refer to:
Companies
* Merc ...
, gadolinium, and
lead.
Contact or absorption of poisons can cause rapid death or impairment. Agents that act on the
nervous system can paralyze in seconds or less, and include both biologically derived
neurotoxin
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature ner ...
s and so-called
nerve gases, which may be synthesized for
warfare 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 a ...
, used as a method of
execution in
gas chambers, almost instantly starves the body of energy by
inhibiting the
enzymes
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
in
mitochondria
A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...
that make
ATP
ATP may refer to:
Companies and organizations
* Association of Tennis Professionals, men's professional tennis governing body
* American Technical Publishers, employee-owned publishing company
* ', a Danish pension
* Armenia Tree Project, non ...
. Intravenous injection of an unnaturally high concentration of
potassium chloride
Potassium chloride (KCl, or potassium salt) is a metal halide salt composed of potassium and chlorine. It is odorless and has a white or colorless vitreous crystal appearance. The solid dissolves readily in water, and its solutions have a salt ...
, such as in the execution of prisoners in parts of the United States, quickly stops the
heart by eliminating the
cell potential necessary for
muscle contraction.
Most biocides, including
pesticide
Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
s, 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), including the
humans who apply the biocides and other
beneficial organisms. 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. An example is "wood alcohol" or
methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...
, which is not poisonous itself, but is chemically converted to toxic
formaldehyde and
formic acid
Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es ...
in the
liver. Many
drug
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via insuffla ...
molecules are made toxic in the liver, and the genetic variability of certain liver
enzymes 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