(Adapted from the U.S. Army Survival Manual)
Successful use of plants in a survival situation depends on
positive identification. Knowing poisonous plants is as important
to a survivor as knowing edible plants. Knowing the poisonous
plants will help you avoid sustaining injuries from them.
HOW PLANTS POISON
Plants generally poison by -
Ingestion. When a person eats a part of a poisonous
Contact. When a person makes contact with a poisonous
plant that causes any type of skin irritation or dermatitis.
Absorption or inhalation. When a person either absorbs
the poison through the skin or inhales it into the respiratory
Plant poisoning ranges from minor irritation to death. A common
question asked is, "How poisonous is this plant?" It
is difficult to say how poisonous plants are because -
Some plants require contact with a large amount of the plant
before noticing any adverse reaction while others will cause
death with only a small amount.
Every plant will vary in the amount of toxins it contains
due to different growing conditions and slight variations in
Every person has a different level of resistance to toxic
Some persons may be more sensitive to a particular plant.
Some common misconceptions about poisonous plants are -
Watch the animals and eat what they eat. Most of the time
this statement is true, but some animals can eat plants that
are poisonous to humans.
Boil the plant in water and any poisons will be removed. Boiling
removes many poisons, but not all.
Plants with a red color are poisonous. Some plants that are
red are poisonous, but not all.
The point is there is no one rule to aid in identifying poisonous
plants. You must make an effort to learn as much about them as
ALL ABOUT PLANTS
It is to your benefit to learn as much about plants as possible.
Many poisonous plants look like their edible relatives or like
other edible plants. For example, poison hemlock appears very
similar to wild carrot. Certain plants are safe to eat in certain
seasons or stages of growth and poisonous in other stages. For
example, the leaves of the pokeweed are edible when it first
starts to grow, but it soon becomes poisonous. You can eat some
plants and their fruits only when they are ripe. For example,
the ripe fruit of mayapple is edible, but all other parts and
the green fruit are poisonous. Some plants contain both edible
and poisonous parts; potatoes and tomatoes are common plant foods,
but their green parts are poisonous.
Some plants become toxic after wilting. For example, when
the black cherry starts to wilt, hydrocyanic acid develops. Specific
preparation methods make some plants edible that are poisonous
raw. You can eat the thinly sliced and thoroughly dried corms
(drying may take a year) of the jack-in-the-pulpit, but they
are poisonous if not thoroughly dried.
Learn to identify and use plants before a survival situation.
Some sources of information about plants are pamphlets, books,
films, nature trails, botanical gardens, local markets, and local
natives. Gather and cross-reference information from as many
sources as possible, because many sources will not contain all
the information needed.
RULES FOR AVOIDING POISONOUS PLANTS
Your best policy is to be able to look at a plant and identify
it with absolute certainty and to know its uses or dangers. Many
times this is not possible. If you have little or no knowledge
of the local vegetation, use the rules to select plants for the
Remember, avoid -
All mushrooms. Mushroom identification is very difficult and
must be precise, even more so than with other plants. Some mushrooms
cause death very quickly. Some mushrooms have no known antidote.
Two general types of mushroom poisoning are gastrointestinal
and central nervous system.
Contact with or touching plants unnecessarily.
Contact dermatitis from plants will usually cause the most
trouble in the field. The effects may be persistent, spread by
scratching, and are particularly dangerous if there is contact
in or around the eyes.
The principal toxin of these plants is usually an oil that
gets on the skin upon contact with the plant. The oil can also
get on equipment and then infect whoever touches the equipment.
Never bum a contact poisonous plant because the smoke may be
as harmful as the plant. There is a greater danger of being affected
when overheated and sweating. The infection may be local or it
may spread over the body.
Symptoms may take from a few hours to several days to appear.
Signs and symptoms can include burning, reddening, itching, swelling,
When you first contact the poisonous plants or the first symptoms
appear, try to remove the oil by washing with soap and cold water.
If water is not available, wipe your skin repeatedly with dirt
or sand. Do not use dirt if blisters have developed. The dirt
may break open the blisters and leave the body open to infection.
After you have removed the oil, dry the area. You can wash with
a tannic acid solution and crush and rub jewelweed on the affected
area to treat plant-caused rashes. You can make tannic acid from
Poisonous plants that cause contact dermatitis are -
Steve's Notes: I've seen a poison ivy rash cleared
up overnight using the juice from jewelweed.
Ingestion poisoning can be very serious and could lead to
death very quickly. Do not eat any plant unless you have positively
identified it first. Keep a log of all plants eaten.
Signs and symptoms of ingestion poisoning can include nausea,
vomiting, diarrhea, abdominal cramps, depressed heartbeat and
respiration, headaches, hallucinations, dry mouth, unconsciousness,
coma, and death.
If you suspect plant poisoning, try to remove the poisonous
material from the victims mouth and stomach as soon as
possible. Induce vomiting by tickling the back of his throat
or by giving him warm saltwater, if he is conscious. Dilute the
poison by administering large quantities of water or milk, if
he is conscious.
The following plants can cause ingestion poisoning if eaten:
Poison and water hemlocks.
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