Poisons of plant origin. The most dangerous poisons from plants. The most dangerous plant poisons

Everyone should know about this!

All about the most poisonous plants - those grown culturally, for medicinal purposes, wild and indoor plants, mushrooms and trees. Poisonous indoor plants You need to know the enemy by sight, as they say. If you came to a garden store to choose a new green pet, or a friend suggested plucking off a sprout, it is worth checking in advance whether the new plant will harm you or your pets, especially animals and children. For example, all plants of the euphorbia, araceae, and amaryllis families have dangerous juice that causes burns on the skin, and if ingested, quite severe poisoning follows - the gastrointestinal tract, mucous membranes, and even the nervous system are damaged.

The popular milkweed is also a poisonous plant.

Potential indoor poisoners include such popular plants as How

poinsettia,

dieffenbachia,

monstera,

philodendron,

beautiful callas,

and even

tulips,

daffodils!

If their juice gets on your skin, you need to immediately wash your hands, and even though you very carefully cut and formed a bouquet, you should not touch your eyes with the same hands. In some plants, for example, nightshade or kutraceae, only some parts are poisonous, as luck would have it, the most attractive to unintelligent children (bright fruits, sometimes tubers). Therefore, you should not keep such flowers in the public domain. House monstera juice is poisonous

However, life-threatening representatives of the flora await us almost everywhere: in the forest, in the meadow, and in the middle zone there are no less of them than in the exotic jungle. Take the same quiet hunt or collecting medicinal herbs: everywhere you need to know which mushroom or flower is best to avoid.

The most poisonous mushrooms The most famous poisonous representative of the mushroom world is, of course,

death cap,

an indispensable ingredient in Baba Yaga’s potion and a one hundred percent guarantee of being sent to the next world if a mushroom picker accidentally gets into the frying pan. The poison contained in the toadstool is resistant to heat, and it also does not disappear from the dried toadstool, so they cannot be eaten in any form. Distinctive features are white plates and a characteristic skirt. Champignons, with which toadstool is confused, also have a skirt, but the plates are dark. Even in toadstools, the leg grows as if from a sac, although this sign is not so accurate - the lower part of the leg is hidden in the soil. Toadstools are included in the list of the most poisonous mushrooms. Various fly agaric mushrooms are also confused with champignons - not bright red ones, but

panther or smelly.

If the brown panther fly agaric most often does not lead to the death of an unlucky taster, then the white stinking fly agaric is almost as poisonous as the pale grebe. The following are deadly poisonous mushrooms -

gallerinas

- disguised as honey mushrooms. They also grow on stumps, of the same color. Only experienced mushroom pickers can tell the difference right away. And this is not

false honey mushrooms:

They are also poisonous, but differ in the shape of their cap. The fly agaric is the brightest and most famous poisonous mushroom. The most insidious mushroom poisoner is called the “beautiful cobweb”.

the most beautiful spider web

Having accidentally slipped into the basket, it is eaten and digested, but its poison is such that the symptoms of fatal poisoning appear after a couple of weeks. No one even assumes poisoning, so most often the case ends in death.

Poisonous plants of Russia And among the green inhabitants of central Russia, quite common species, familiar to almost everyone, are very poisonous. Take, for example, a plant like

aconite

, also known as a wrestler. Tall grass with noticeable pipe flowers is completely poisonous, the leaves and roots are especially dangerous. A couple of grams of any part of aconite, ingested, can kill an adult - death occurs from respiratory arrest. Previously, aconite was deliberately used for bad purposes, for example, to poison bladed weapons with it. Ocanite is a very poisonous plant. It is also used in magic. It is also poisonous.

belladonna,

as well as her close relatives

Datura and

henbane

- they are all from the nightshade family. We also have the famous hemlock, aka

Veh is poisonous.

It is often mistaken for an edible plant like celery, as its roots have a pleasant smell and taste. Hemlock poison affects the nervous system. Cattle that accidentally eat it along with other grass also suffer from hemlock - 200 g of roots kill a cow. Hemlock - a plant with a deadly poison Known to everyone and

wolf's bast (wolf berries),

for Serg - compare with buckthorn -

The wolfberry has a berry directly to the branch, while the buckthorn has a small stalk.

And

raven eye

- children are most often poisoned by their unusual berries. There are few deaths, since the berries, to put it mildly, are much more attractive in appearance than in taste, so a large dose can only be eaten deliberately. Another danger is

hogweed

- its giant umbrella inflorescences are often found along roads. When hogweed juice gets on the skin or simply comes into contact with the leaves, human skin becomes extremely sensitive to ultraviolet radiation. The result is severe sunburn, even in the shade. And if you eat hogweed, then in addition to somatic signs of poisoning, even reversible mental disorders are observed. Popular forest and wildflowers are also very poisonous - for example,

buttercups, lilies of the valley

Lilies of the valley often grown in gardens as ornamental, but all their parts are poisonous, from roots to berries. You can even be poisoned by water in which a bouquet of lilies of the valley stood. The poison affects the activity of the heart. But buttercups are dangerous only when fresh - when dried, the poison is destroyed, so buttercup hay is safe for animals. Lily of the valley is not only a rare, but also a poisonous plant. It is interesting that almost all of the listed poisonous plants are widely used in medicine, like other plants not mentioned above. For example, celandine in dermatology, hemlock in oncology and much more. The question is quantity: the wrong dosage of a medicinal plant kills. But there are also representatives of the flora that you should not even approach, let alone consume in homeopathic doses. Moreover, they look, so to speak, quite everyday. It's good that they don't grow here. The most poisonous plant in the world So, the most poisonous plant in the world from the Guinness Book of Records is called manchinella. This tree is a common deciduous tree native to the Bahamas and the Caribbean. Everything about it is poisonous - the apple fruits, the juice, which causes terrible burns and swelling, and the bark. It is difficult to cut it down, and it is not even possible to burn it: the smoke is also poisonous and causes blindness! Manchinella is the most poisonous plant in the world. In general, you just need to stay away from manchinella. Therefore, it is often fenced off with a red marker. Remember and avoid. But the most poisonous substance on earth is not a plant. According to uznayvse.ru, the most dangerous creature in this regard is the box jellyfish.

Introduction

The study of such an issue as natural poisons of plant and animal origin is relevant for a doctor of any specialty, since they are a common cause of acute poisoning.

Speaking about natural poisons, we mean, first of all, substances that enter the body with food, upon contact with intact skin or wound surfaces, when a poisonous insect or animal is introduced into the human body with a special apparatus and cause poisoning in humans and animals.

Most natural poisons have a polytropic effect and high toxicity, which determined their use for combat purposes.

The basis of chemical weapons is made up of toxic chemical substances, including chemical agents, protein toxins and herbicides (phytotoxicants) for military purposes. This lecture discusses, first of all, poisons that a military doctor may encounter during his career.

Study Question #1.General characteristics of poisons and toxins of plant and animal origin

Natural poisons in their toxic properties are tens and hundreds of times superior to known chemical warfare agents.

Toxins- these are chemical substances of protein nature, which are mainly waste products of plant, animal, microbial or other origin, have high toxicity and the ability to have damaging effects on the human and animal body.

Often in the specialized literature, the term “toxin” is not sufficiently justifiably extended to non-protein toxic substances of natural origin (for example, saxitoxin, tetrodotoxin, etc.). When used correctly, the term “toxin” should refer to toxic substances of a protein nature.

Toxins are solid substances and are unstable military toxic chemicals that do not contaminate military weapons and equipment. Personnel affected by toxins are not contagious and do not pose a danger to others.

A significant difference between toxins and poisons of a non-protein nature is their ability, when they enter the human body, to exhibit antigenic properties and develop immunity in it, which is not characteristic of natural poisons of a non-protein nature.

All toxic chemicals of natural origin, regardless of their composition and natural origin, the defeat of which is not accompanied by the body's immune response are called natural poisons.

Toxins are a type of toxic chemical warfare agents and are used as the active principle of chemical weapons. Foreign military experts consider toxins as the basis of the so-called “toxin weapon”, as one of the independent types of chemical weapons.

Some experts tend to consider toxin weapons as a type of biological weapon. However there are strong argumentsinclusion of toxins in the chemical weapons system, namely:

toxins can be produced not only by microorganisms, but also by animals and plants;

in their structure, toxins are no different from ordinary chemical compounds and can be obtained synthetically;

unlike biological agents, toxins are not viable and cannot reproduce under any conditions;

toxins do not have an incubation period; the period of latent action depends only on the dose and routes of entry into the body;

the combat use of toxins can be carried out on the basis of the same principles and methods that are used in the use of chemical weapons.

Classification of toxins

The most widespread classification of toxins is based on their origin, their role in the life of the producing organism, and their toxicological effect on the affected organism.

Depending on the source of origin, all toxins are divided into 3 groups:

phytoxins - toxins of plant origin;

zootoxins - toxins of animal origin (part of the venom of some animals);

microbial toxins - produced by many types of microorganisms and are the cause of poisoning and disease.

This classification can be expanded

4 group - synthetic toxins. Today such toxins do not exist. Although, intensive research work is underway to obtain them.

There are exotoxins and endotoxins:

Endotoxins are metabolic products that function inside cells as metabolites. They are released into the external environment only after cell death, for example, after the decomposition of microorganisms. As a rule, it is a complex of polypeptides with polysaccharides, lipids or lipopolysaccharides.

Exotoxins are also produced during intracellular metabolism, but are released by producer cells into their environment during life.

Typically, exotoxins are proteins that retain their biological activity outside the cell. This is an important feature of them, because... this makes it possible to create reserves of exotoxins and use them for various purposes, including chemical warfare.

According to the effect on the body, toxins (mainlyexotoxins) are conventionally classified into:

neurotoxins;

cytotoxins (effector toxins);

enzyme toxins;

enzyme inhibitor toxins.

Neurotoxins specifically act on the nervous system, disrupt the transmission of nerve impulses at different stages. They can cause disruption of the membrane permeability of nerve cells to ions; reduce or increase the penetration of mediators into the synaptic cleft; block receptors of the postsynaptic membrane or, on the contrary, stimulate its restructuring.

Cytotoxins are capable of disrupting the structures of various biological membranes, thereby changing cellular permeability and the course of intracellular processes. In some cases, cytotoxins can destroy membranes: dissolve the membranes of red blood cells, leukocytes, lymphocytes, platelets, and blood macrophages.

Enzyme toxins contribute to the hydrolytic breakdown of individual structures of cell components: proteins, nucleic acids, polysaccharides, lipids, thereby causing disruption of normal physiological reactions in humans and animals.

Enzyme inhibitor toxins capable of disrupting biocatalytic control of many metabolic processes. It should be noted that exotoxins with a mixed type of pharmacological action are known.

Toxins are also subject to the tactical classification of toxic substances, according to which they are all divided into lethal toxins and toxins that temporarily incapacitate living forces.

Study Question #2. Toxicological characteristics of poisonous plants.

Poisonous plants are called those, contact with which or ingestion of them, even in small quantities, causes a health disorder.

Classification of poisonous plants:

Actually poisonous plants

toxicity is a permanent or temporary sign of their normal development;

characteristic of a plant species or genus;

have a toxic effect in the presence of specific conditions.

Conditionally poisonous plants

toxicity is a random feature, usually not characteristic of normal development;

arises due to various circumstances in an individual of a harmless species or genus;

refer to random properties.

The toxicity of poisonous plants can vary dramatically depending on the stage of their development, local environmental, climatic, soil and other conditions.

The sensitivity of humans and animals to the effects of poison is different: horses and dogs tolerate 10 times, pigeons 100 times, frogs 1000 times larger doses of opium alkaloids than humans (per 1 kg of body weight).

Classification of plant poisons by degree of toxicity:

Particularly toxic (monkshood, ricin, phalloidin) - lethal dose upon admission per os no more than 0.001 g;

Highly toxic (anabasine, atropine, veratrine, nicotine, hydrocyanic acid, cicutotoxin) - lethal dose upon admission per os from 0.001 to 0.05 g;

Highly toxic (strychnine) - lethal dose 0.05-2.0 g upon admission per os;

Toxic (caffeine, ergot, quinine) - lethal dose 2.0-20.0 g upon admission per os.

Plant poisons are characterized by selective toxicity.

Damage to the central nervous system with M - anticholinergic syndrome is observed in case of poisoning with henbane, datura, belladonna, with nicotine-like syndrome with poisonous milestone, hemlock, spotted, horsetail. Damage to the CVS is caused by foxglove, lily of the valley, adonis, liver damage - pubescent heliotrope, cross grass, skin damage - hogweed, wolf's bast, ranunculus, spotted hemlock.

With damage to several organs and systems:

CNS and heart - aconite;

heart and gastrointestinal tract - Lobel's hellebore;

Gastrointestinal tract and central nervous system - bittersweet nightshade, wolf's bast.

Poisonous These are plants whose contact with or ingestion, even in small quantities, causes health problems.

There are:

1. Actually poisonous plants:

Toxicity is a permanent or temporary sign of their normal development;

Toxicity is characteristic of the entire plant species or genus;

The toxicity of the plant manifests itself in the presence of specific conditions.

2. Conditionally poisonous plants:

Toxicity is a random trait, usually not characteristic of normal development;

Toxicity occurs due to various circumstances in an individual representative of a species or genus that is safe for humans;

Toxicity refers to random properties.

According to selective toxicity, plants can be divided into:

1. Plants, in the clinical picture of poisoning of which the leading syndrome is damage to the central nervous system:

a) with anticholinergic syndrome: henbane, datura, belladonna.

b) with nicotine-like syndrome: poisonous hemlock, spotted hemlock, horsetail.

2. Plants that cause predominant damage to the heart (plants containing cardiac glycosides): foxglove, lily of the valley, adonis, hellebore.

3. Plants that cause predominant liver damage: pubescent heliotrope, crossweed, pink bitterling.

4. Plants that cause skin lesions: hogweed, wolf's bast, ranunculus, spotted hemlock.

5. Plants that cause predominant damage to the gastrointestinal tract: colchicum, wolf's bast, castor bean (Turkish hemp, castor oil), buckthorn, spurge, nightshade.

6. Plants that have a toxic effect on several organs and systems simultaneously:

Aconite - on the central nervous system and heart;

Lobel's hellebore - on the heart and gastrointestinal tract ;

Nightshade is bittersweet, wolf's bast - on the gastrointestinal tract and central nervous system.

The toxicity of plants to mammals, humans and other living beings is realized through the production of special chemical compounds - phytotoxins. Phytotoxins are substances with different structures and unequal biological activity. Being products of plant metabolism, phytotoxins sometimes perform protective functions, scaring away potential consumers; however, for most of the above compounds, their significance for plant life remains unknown. Among phytotoxins, various classes are distinguished: alkaloids, organic acids, terpenoids, lipids, glycosides, saponins, flavonoids, coumarins, anthraquinones, etc.

Alkaloids(from the Latin term “alkali” - “alkali”, which, in turn, comes from the Arabic al qualja - “plant ash”) - the most numerous phytotoxins, which are nitrogen-containing organic heterocyclic bases. In plants, alkaloids are usually found in the form of salts of organic acids - oxalic, malic, tartaric, citric, etc. Currently, about 5,000 alkaloids are known, many of which are highly toxic to mammals and humans. As a rule, alkaloids are colorless crystalline compounds with a bitter taste, practically insoluble in water, but highly soluble in organic solvents. Alkaloid salts, on the contrary, are highly soluble in water, but do not dissolve in organic solvents. The selectivity of the effects of alkaloids on various organs and systems allows many of them to be used as medicines. Alkaloids are represented by various groups of chemical compounds that differ in the nature of the heterocycle (Table 32).

Table 32 – Main types of alkaloids and plants producing them

Plant poisons

MONSKING, or WRESTLER. Belongs to the genus of herbaceous perennial plants of the ranunculaceae family. It was first used for medical purposes in the 18th century by the Austrian physician Sterk. Today, aconite is used in homeopathy for pneumonia, fever and other pathological conditions. The plant is poisonous. If poisoning is noticed in a timely manner, the patient should be given an emetic. Symptoms of poisoning are pain and burning in the mouth and tongue, increased sweating, frequent urge to urinate, tachycardia, dilated pupils, darkening of the eyes, headache, nausea. As intoxication progresses, vomiting, stomach cramps, convulsions and delirium appear, then respiratory arrest occurs. If help is not provided in a timely manner, poisoning ends in death. The toxic effect of the plant is associated with the alkaloid it contains, aconitine, which causes convulsions and respiratory arrest.

BELLADONNA, or BELLADONNA. Plant of the nightshade family. In the past, women would put belladonna in their eyes to make them shine and dilate their pupils. In medicine, belladonna is used as an antispasmodic. The leaves of the plant are used as the starting product for making medicine. Preparations based on belladonna prevent the stimulating effect of acetylcholine (a substance involved in the transmission of nervous excitation in the central nervous system, the endings of parasympathetic and motor nerves, autonomic nodes), reduce the secretion of the salivary, lacrimal, sweat and bronchial glands. Taking such medications reduces the tone of the muscles of the gastrointestinal tract and gallbladder ducts, dilates the pupils, prevents the outflow of intraocular fluid, and increases intraocular pressure. Preparations based on belladonna are prescribed for gastric and duodenal ulcers, cholelithiasis, bradycardia, hemorrhoids and other diseases. Such drugs are contraindicated in case of hypersensitivity to their components, glaucoma, prostate hypertrophy. Taking drugs based on belladonna may be accompanied by psychomotor agitation, photophobia, intestinal atony, rapid heartbeat, urinary retention, and dry mouth. With mild belladonna poisoning, difficulty breathing and speech, tachycardia, hoarseness, dilated pupils, visual hallucinations, and delirium are observed. Severe poisoning is accompanied by convulsions, a sharp increase in body temperature, shortness of breath, cyanosis of the mucous membranes, and a sharp decrease in blood pressure. Death occurs as a result of paralysis of the respiratory center and vascular insufficiency.

BLACK HEBREW (MAD GRASS, RAB). Plant of the nightshade family. The leaves and seeds of the plant are used in pharmaceuticals to treat cramps, toothache, and cough. Alkaloids contained in henbane have an antispasmodic effect on smooth muscles, increase intraocular pressure, promote pupil dilation, cause paralysis of accommodation and tachycardia, and affect the central nervous system. In combination with mandrake, belladonna and datura, henbane is used as an analgesic with a psychoactive effect, manifested in euphoria and visual hallucinations. Even small doses of henbane are toxic. The plant is especially dangerous for children, who may be attracted by its bright appearance. Therefore, henbane is destroyed in populated areas. Symptoms of henbane poisoning include dilated pupils, dry mouth, hoarseness, rapid heartbeat, extreme thirst, and headache. In case of untimely first aid, the victim develops a coma.

DEATH CAP. A mushroom from the genus of fly agarics, the most poisonous mushrooms. It contains the alkaloids phalloidin, phallin and amanitin. The lethal dose of amanitin is 0.1 mg/kg. Mushroom pickers may confuse toadstool with edible mushrooms, such as champignons and green russula. Poisoning is possible if you mistakenly eat a poisonous mushroom. Heat treatment does not reduce the toxic properties of toadstool. For poisoning, it is enough to eat 25–30 g of mushroom. Characteristic signs of poisoning are convulsions and jaw clenching. A few hours after the onset of intoxication, the patient experiences vomiting, intestinal colic, muscle pain, severe thirst, and diarrhea (sometimes mixed with blood). An enlarged liver is also possible. The pulse gradually weakens and becomes thread-like. Death occurs as a result of acute hepatitis and heart failure. The danger of poisoning with toadstool is that the symptoms of intoxication do not appear immediately. The first signs may appear within 6–24 hours as vital organs are damaged.

SPECKED HEMMON, or SPOTTED HELMIC. A perennial plant of the Umbelliferae family with an unpleasant odor. Externally, it resembles wild carrots, since both plants have a tap root. The plant is poisonous. All its parts contain the alkaloid coniine, which paralyzes the respiratory muscles. In medicine, hemlock is used as an external remedy. When poisoned by the plant, nausea, vomiting and diarrhea appear, the pupils dilate, the limbs become cold and immobilized, and breathing becomes difficult. First aid for poisoning is gastric lavage and a salt laxative. Particular attention should be paid to breathing and, if necessary, artificial respiration should be performed. Diuretics are indicated to quickly remove poison from the body. In toxic doses, the plant causes paralysis. In ancient times it was used as a nerve poison.

HEMP. Plant of the hemp family. It contains narcotic substances - cannabinoids - and is used as a starting material for the preparation of marijuana and hashish. The largest part of the narcotic substances is found in the resin released from the flowers of female plants. Resin is necessary to retain moisture and protect the flower from high temperatures during the propagation period. The production and sale of drugs containing cannabis is prohibited in most countries of the world. The use of drugs containing cannabis leads to depression of the central nervous system. First, nervous excitement, tinnitus, dilated pupils, a state of euphoria, laughter, and visual hallucinations are observed. The second phase of poisoning is characterized by a depressed mood, turning into long and deep sleep with a decrease in body temperature and a slower pulse. If cannabis is taken orally, the patient is given a gastric lavage; if there is increased nervous excitement, an injection of a 2.5% solution of aminazine is given intramuscularly. Cannabinoids relieve symptoms of AIDS and advanced cancer. The last months of life of such patients are accompanied by severe pain, loss of appetite and exhaustion. Cannabinoids increase appetite and relieve pain, so their use in this category of patients may be beneficial.

FALSE OPINION, or FALSE OPINION. Belongs to a group of poisonous mushrooms similar to honey mushrooms. The cap of false mushrooms is convex, with a bump in the center, yellowish in color, the flesh is light yellow. The mushroom has a bitter taste. It grows, as a rule, on the stumps of deciduous trees or next to them, sometimes on the trunks of living trees. False honey fungus can be found from late June to September. From August to mid-October, another type of false honey fungus grows more often - with a brick-red cap. The most dangerous representative of the group is the false honey fungus. All of these mushrooms cause irritation of the digestive tract, nausea, vomiting and diarrhea. Poisoning with false honey mushrooms in most cases occurs in a mild form. It must be taken into account that poisoning can also occur when edible mushrooms are consumed. The reason is improper cooking. Some mushrooms can only be pickled; they cannot be eaten boiled or fried. Another reason for poisoning with edible mushrooms is the consumption of old specimens in which decomposition processes have already begun. The poisonous effect of false mushrooms is associated with the content of the poisons phalloidin and maniin in them.

OPIUM (HYPOTICS) MAC. Herbaceous plant of the poppy family. It grows in China, India, Afghanistan, Asia Minor and Central Asia. From the unripe capsules of the plant, opium is obtained, which is used to make medical and narcotic drugs. Poppy seeds are used to make industrial oil and are also added to baked goods. The narcotic substance, made from seeds and other parts of the poppy, is highly toxic. Its constant use leads to the formation of persistent drug addiction. As a result of opium use, irreversible changes occur in the central nervous system. Poppy seeds contain glycosides that cause visual and auditory hallucinations or deep sleep. An overdose of the drug is fatal. This type of drug addiction is difficult to treat.

HYDROGENIC ACID, or HYDROGEN CYANIDE. Colorless liquid with the smell of bitter almonds. It is obtained from fruit seeds (peaches, apricots, plums, etc.), as well as chemically. Hydrocyanic acid is a highly toxic substance. When it enters the body, it causes tissue hypoxia. When inhaling vapors of a highly concentrated substance, a scratching sensation in the throat, headache, chest pain, nausea, and vomiting occur. As the symptoms of poisoning increase, the pulse rate decreases, convulsions begin, loss of coordination and then consciousness occurs. Ingestion of poison causes clonic-toxic convulsions, instant loss of consciousness, and paralysis of the respiratory center. Death usually occurs within a few minutes. For hydrocyanic acid poisoning, 2 groups of antidotes are used. The first group of substances, interacting with hydrocyanic acid, forms non-toxic products. It includes drugs such as colloidal sulfur, polythionates, aldehydes, ketones, etc. The second group of antidotes promotes the formation of methemoglobin in the blood. This includes methylene blue, salts and esters of nitrous acid.

CHICUTA (POISONOUS VEKH, CAT PARISH, MUTNIK). A poisonous plant common in Europe. It has a pleasant smell, reminiscent of carrots. The largest amount of toxic substances is contained in the rhizomes of the plant. 100–200 g of rhizomes is enough to kill a cow, 50 g is fatal to a sheep. The seeds and rhizomes of the poisonous plant are used to prepare hemlock oil (cicutol). The root resin contains cicutoxin. If it is taken orally, headache, nausea, vomiting, dizziness, and foam at the mouth occur. The victim's pupils dilate and epileptic seizures begin, which can result in paralysis or death. First aid for poisoning is gastric lavage with an activated carbon solution. In folk medicine, ointments and tinctures are made from hemlock rhizomes to treat rheumatism, gout and some skin diseases. The plant is also used in homeopathy. Hemlock is considered the most powerful plant poison. Its rhizome is most poisonous in late autumn and early spring. The plant retains its toxic properties even when exposed to high temperatures and during long-term storage. The largest percentage of cases of animal poisoning by hemlock occurs in the spring.