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 substances.
Some persons may be more sensitive to a
Some common misconceptions about poisonous plants
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.
- Watch the animals and eat what they eat.
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 possible.
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.
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 "Universal
Edibility Test." Remember, avoid --
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
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, and blisters.
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
- Poison ivy.
- Poison oak.
- Poison sumac.
- Rengas tree.
- Trumpet vine.
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
If you suspect plant poisoning, try to remove the
poisonous material from the victim's 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:
- Castor bean.
- Death camas.
- Physic nut.
- Poison and water hemlocks.
- Rosary pea.
- Strychnine tree.
See Appendix C for photographs and descriptions
of these plants.