Poison refers to any substance that is harmful
to health or dangerous to life. The substance
can be one that is produced by the body or
one that is introduced to the body from the
outside. Some toxicologists (scientists who
study poisons) state that any substance used
in excess can be a poison.

This is true even for substances that are
generally good for you when used in
moderation. A good example would be water.
When used in moderation, water is essential
to maintaining life and has numerous health
When eaten by children due to it's
sweet tase, lead paint acts as a type
of poison.
However, consuming too much water in too short a period of time can lead to water
poisoning (or water intoxication) which can be deadly because it disturbs the normal
balance of electrolytes in the body. Electrolytes are chemical substances that are able to
conduct electricity after they are melted or dissolved in water. They play an important
role in the functioning of cells.

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Poison can also be defined as a substance that prevents a chemical reaction or
inactivates a catalyst. A catalyst is a substance that speeds up a chemical reaction.
Thus, if a catalysist is inactivated it prevents it from speeding up a chemical reaction.
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Poisons can be ingested, inhaled, or absorbed into the body in
small or large amounts. Poisons are clinically divided into
those that respond to specific treatments and those which do

Researchers continue to develop antidotes for new poisons
(such as snakebites), but at present there are relatively few
effective antidotes. The most important aspect in treating
poisoning is to maintain blood circulation and breathing.

Poison comes from the Latin word "potio" meaning "potion."