This summer, which plants to watch out for to avoid poisoning?


We often forget that all parts of plants can be toxic: leaves, bulbs, fruits or berries, seeds, flowers, roots, stems, sap or latex... So much so that, throughout the year, the Centers poison control receive up to 10 calls due to exposure to ornamental or wild plants.

Three-quarters of the cases are young children or people with cognitive impairments, who grabbed leaves, flowers or berries and put them in their mouths out of ignorance of the risk or a taste for exploration.

In 10% of other cases, adults consumed plants picked or collected from the wild or their vegetable patch; they may have shared their meal with young children.

The remaining appeals relate to exposures most often by eye or skin contact to the sap or latex of leaves or stem, during gardening, maintenance of houseplants or during other accidental circumstances.

A third of people exposed to plants report symptoms (see figure below). 20% of young children (under 6 years old) who have put part of the plant in their mouths show symptoms. Often the unpleasant or pungent taste of the plant limits its ingestion, like the vigilance of adults. Adults are symptomatic in one out of two cases, whether after consumption or otherwise.

Since 2012, the number of calls (for exposure with or without symptoms) has increased from 7000 to almost 10
Number of calls per year associated with plant exposures, recorded by poison control centers between 2012 and 2021.
SICAP, Author provided

More frequent exhibitions in the summer

The risks associated with exposure to plants depend on the development and germination cycle of each plant. If the most frequent confusion concerns toxic bulbs (narcissus, daffodil, iris, gladiolus, tulip, hyacinth, amaryllis, crocus...) and edible bulbs (onion, garlic, shallot...), which occur all year round, the summer period is particularly conducive to confusion of berries, small fruits and leaves or roots.

Thus, half of calls to poison control centers for this type of reason are recorded in the summer, between June and September (see figure below) – a third of recorded confusion occurs during this season, and the month of August is the busiest (with 15% of annual calls for exposure to plants).

Over a year, it is during the summer months that calls are most frequent
Number of cumulative calls per month associated with exposure by plants, recorded by poison control centers between 2012 and 2021.
SICAP, Author provided

In a study on the confusions of toxic and edible plants recorded by poison control centers between 2012 and 2018,National Agency for Food, Environmental and Occupational Health Safety (ANSES) and the poison control centers had established the most frequent and/or the most serious confusions according to the seasons.

Subsequently, ANSES issued a checklist on the risks of food confusion of toxic and edible plants according to the seasons.

This work makes it possible to point out the plants to which we must pay particular attention this summer.

[Nearly 70 readers trust The Conversation newsletter to better understand the world's major issues. Subscribe today]

Beware of ingesting toxic berries!

The berries are small fleshy fruits (containing one or more seeds, the pips) which mature in the summer, which makes them attractive. Often within the reach of children exploring their environment, they are also picked to be eaten, prepared into jam, jelly or syrup.

Generally red or black in color when they mature, the poisonous and edible berries may look alike. Unripe, inedible fruits are green in color. The black berries can be green and then red before reaching maturity, which can encourage mistakes.

Depending on the substances they contain, toxic berries can cause (most often) digestive disorders, but also cardiac, respiratory and neurological disorders. The effects can be serious from the ingestion of a few berries. Here are the ones to watch out for first.

  • belladonna (Belladonna atropa)

You have to be particularly careful with the berries of these plants of the Solanaceae family such as belladonna, which grow easily in clearings or on rubble.

Its berries, black and shiny, look like small cherries and have a deceptively sweet and sweet flavor because they are far from harmless. They contain indeed tropane alkaloids (atropine, hyoscyamine, scopolamine), real paralyzers of the nervous system, which causes among other things a dilation of the pupil, an acceleration of the heart rate, headaches, ringing in the ears, hallucinations …

If all parts of the plant are toxic, the ingestion of a few berries is enough to cause disorders of consciousness, even convulsions and a coma that can lead to death.

  • nightshades

Other poisonous berries, containing alkaloids, can be confused with edible berries such as black nightshade (Solanum nigrum), moderately toxic, or bittersweet nightshade (Solanum dulcamara), with red berries, sometimes nicknamed “dog killer”. All are toxic to humans and pets.

  • honeysuckles

The Caprifoliaceae family includes harmless members, such as the Blue Honeysuckle (Lonicera caerulea kamtschatica), and other dangerous ones, including blackberry honeysuckle (L. nigra).

The black berries of L. nigra are welded in pairs. They contain saponosides (or saponins), also present in other parts of the plant, which have irritating properties for the mucous membranes.

Their consumption can be responsible for severe digestive disorders: vomiting, abdominal pain but also bloody diarrhea, etc.

Its berries can possibly also be confused with wild blueberries (Vaccinium myrtillus), which share the same environment but whose berries are bluish and isolated.

Its "cousin", the Blue Honeysuckle, or Mayberry or Blue Haskap, is shrubby and produces in the spring edible berries with a characteristic acidulous taste, elongated and bluish, covered with bloom (waxy and slightly powdery layer which covers the surface as in blueberries).

  • elderberries (Sambucus sp.)

Certain elderberries, shrubs and herbaceous plants of the Caprifoliaceae family can also be poisonous or edible. Their berries appear, still green, from the end of June and reach maturity between August and September. Ripe fruits are laxatives eaten raw.

Unlike black elderberries (Sambucus nigra), edible and cooked in jam or jelly, elderberries hièble or yèble (Sambucus ebulus) are toxic and can be responsible for severe digestive disorders (abdominal pain, diarrhea, vomiting, etc.).

How to distinguish them? If they have the same black fruits, the dangerous fruits of the elderberry are erect upwards, while those of the black elderberry are hanging down. In addition, unlike the black elderberry, the elderberry is a herbaceous plant and therefore does not make wood.

Other risks of serious summer poisoning

  • by the leaves

In summer, some plants, especially mountain plants, flower late (between June and September), and edible and poisonous plants can be confused when looking for their leaves – eaten in salads, herbal teas or decoctions. The confusion is explained by their similar morphology before flowering and sharing the same habitat.

Foxglove (digitalis purpurea), toxic or even deadly, can thus be confused with comfrey (Symphytum officinalis), which is an occasional edible (prolonged daily consumption may be toxic to the liver). All parts of foxglove are poisonous. If swallowed, nausea, vomiting, diarrhea, drowsiness or restlessness, headaches, visual disturbances may be observed. In the most serious cases, a slowing of the heart rate, going as far as cardiac arrest, can occur.

Attention, confusions between toxic and edible bay leaves, consumed in decoction, culinary preparation or infusion, are described throughout the year. If the bay leaf sauce (Laurus nobilis) is edible, the oleander (nerium oleander) is highly toxic. To a lesser extent, cherry bay leaves (Prunus laurocerasus) are also toxic.

  • by the roots

The yellow gentian (Gentian lutea) is sought after in summer for its roots in order to prepare aperitifs, wines or liqueurs. This plant, edible, can be confused with the white veratre (A true album), highly toxic due to the alkaloids contained mainly in its roots.

The case of phytophototoxic plants

Finally, it should be noted that during leisure activities on sunny days (picnics, gardening, walks in the forest or in parks, etc.), a particular risk concerns exposure to so-called "photosensitizing" plants: those these contain substances (furocoumarins) which become toxic under the effect of ultraviolet rays.

This is the case, for example, of aromatic plants such as parsley (Petroselinium crispum), common fennel (Foeniculum officinale), dill (Anethum graveolens), angelica (angelica archangelica) but also fruit trees such as the fig tree (ficus carica) or the lemon tree (Citrus limon) and other citrus fruits.

A skin burn, sometimes intense with redness, pain, even blisters, can be observed on exposed areas (hands, forearms, etc.) under the effect of the sun, several hours after having been in contact with the plant.

The right steps to prevent poisoning

To avoid the risk of poisoning, especially in summer, ANSES and the poison control centers recommend:

  • Keep children away from plants at risk and make children aware of the dangers associated with picking;
  • Do not eat the plant picked up if in doubt about its identification, including those picked from the orchard or vegetable patch;
  • Be vigilant about the harvest period (flowering, fruiting, etc.), with regard to the life cycle of the plant;
  • Photograph the harvest to facilitate identification in the event of poisoning;
  • Stop eating immediately if the plant has an unusual or unpleasant taste;
  • Do not pick armfuls (mainly leaves), to avoid mixing toxic and edible species;
  • Thoroughly wash and sort the plants before consuming them;
  • Avoid direct skin contact with photosensitizing plants: if necessary, wear gloves and long, covering clothing to protect the skin from the sun.

Finally, if online plant recognition applications (PlantNet type) can be used to provide initial information, they should not be the only means of identification. The error risk of these applications is not known. If in doubt, do not hesitate to call on a pharmacist or a botanist from a local association.

In case of intoxication:

  • In the event of severe disorders or signs of vital distress (difficulty breathing, loss of consciousness, etc.), immediately call 15 or 112 or 114 for people who are deaf or hard of hearing;
  • If a child has put leaves or berries in their mouth, rinse the inside of their mouth with a damp cloth, wash their hands, and call a poison control center ou see a doctor in case of symptoms or in the slightest doubt about the identification of the plant;
  • Do not wait for symptoms to appear to take the advice of a poison control center in the event of ingestion of a toxic plant;
  • These plants are also toxic to animals. If swallowed, immediately contact a veterinary poison control center.

The author thanks Gael Le Roux, clinical toxicologist pharmacist at the Center antipoison et Toxicovigilance Grand Ouest at the University Hospital of Angers, for his expert review of the article.

Sandra Sinno Tellier, Public health physician, specialized in epidemiology and toxicology, National Agency for Food, Environmental and Occupational Health Safety (ANSES)

This article is republished from The Conversation under Creative Commons license. Read theoriginal article.

Recent articles >

Summary of news from June 2, 2023

outlined-grey clock icon

Recent news >