What are plant poisonings?
Plant poisonings are the adverse consequences from ingesting or coming into contact with a poisonous plant or a substance from the plant. Poisoning may come from any part of the plant or the fruits, berries, leaves, stems, or roots of the plant. The toxicity depends on the dose. Some plants are poisonous at all concentrations, while others are toxic at high concentrations or with overexposure. A plant poisoning diagnosis is usually based on the patient’s or family’s report and the patient’s symptoms; blood and urine tests can help in some cases.
Plant poisoning symptoms range from no symptoms to mild gastrointestinal symptoms and rashes to severe illness; some plant poisonings are fatal. Symptoms may be delayed. A person who has chewed castor beans, which contain the highly toxic substance ricin, may experience delayed vomiting and diarrhea, followed by neurological symptoms. Hemlock poisoning symptoms, in contrast, occur within 15 minutes.
In general, plant poisonings in the United States involve young children who have accidentally ingested a small quantity of a poisonous plant. Childhood fatalities from plant poisonings are rare. Serious illness and death are more likely to occur in adults, either from deliberate ingestion of a known poisonous plant (for self-harm or substance abuse) or from eating a plant, such as a mushroom thought to be edible.
Most plant poisonings are mild and require observation for a few hours. If the plant substance is burning or irritating and the person is conscious, offer milk or water, then call Poison Control at 1-800-222-1222 for next steps.
For life-threatening toxicities, plant poisoning first aid includes checking the person’s airways, breathing and circulation (ABCs). Maintaining breathing and stabilizing the heart are the most critical steps.
Call 911 for immediate assistance if the person has:
- Collapsed or is unconscious (not responsive to your voice or touch)
- Difficulty breathing
Always call Poison Control at 1-800-222-1222 if you, or someone you know, has ingested or come in contact with a known or suspected poisonous plant, which includes wild mushrooms. Do not wait for symptoms to appear.
What are the types of poisonous plants?
Highly toxic plants include:
- Castor beans and jequirity beans
- Hemlock (Cicuta species)
Other poisonous plants include (but are not limited to):
- Autumn crocus
- Azalea (rhododendron)
- Deadly nightshade (Atropa belladonna)
- Elephant ear
- Jerusalem cherry
- Jimson weed
- Morning glory
- Mountain laurel
- Nightshade (Solanum species)
- Peace lily
- Poison ivy, poison oak, poison sumac
- Pothos ivy
- Rosary pea
Poisonous foods, seeds and/or leaves include:
- Apple seeds and leaves
- Apricot, cherry, peach, plum, and nectarine seeds and leaves
- Potatoes, particularly green potatoes and the green plant parts including leaves, tubers and sprouts
- Rhubarb leaves
- Unripe tomatoes
What are the symptoms of plant poisonings?
Plant poisoning symptoms may involve several different areas of the body, including the gastrointestinal, cardiac, neurologic, respiratory, dermatologic, and hematologic (blood) systems. Symptoms may occur within minutes or be delayed after ingestion, depending on the plant toxin and the amount. Do not wait for symptoms to appear. Immediately call Poison Control at 1-800-222-1222. You’ll speak with experts who can advise the next steps, such as contacting your doctor or going to the hospital.
Symptoms of highly toxic plant poisonings
Oleander, foxglove and lily-of-the valley contain cardiac glycosides. These substances act like digoxin, a heart medication derived from these plants. Signs and symptoms of poisoning include:
- Hyperkalemia (high levels of potassium in the blood)
- Irregular heart rate
Azaleas, rhododendron and related plants contain grayanotoxins, which act on the nervous system and heart. Plant poisoning is usually the result of eating or chewing on the leaves. Tea brewed from the leaves and honey from the nectar are also toxic. Symptoms include:
- Slow heart rate (bradycardia)
- Slow respiratory rate
Continued effects resemble symptoms of cardiac glycoside poisoning (e.g., oleander).
Hemlock poisoning is from ingesting water hemlock (from the genus Cicuta). These plants contain cicutoxin, which acts on the central nervous system and causes seizures. Symptoms typically occur within 15 minutes. Fatal poisonings typically follow this sequence:
- Vomiting, nausea and diarrhea
- Dilated pupils
Nicotine from tobacco plants is a powerful chemical that acts on the nervous system. Coniine, from poison hemlock (different from water hemlock) is related to nicotine. These toxins produce what’s known as cholinergic syndrome. Signs and symptoms of ingesting nicotine-containing substances (such as eating a cigarette or from accidental exposure to nicotine replacement products including discarded nicotine patches) include:
- Constricted pupils
- Dry mouth (initially)
- Muscle weakness
- Slow or rapid heart rate
- Tremor, seizures and coma
Green tubers and potato sprouts contain a compound related to nicotine. Ingesting a small amount causes gastrointestinal upset, but consuming large quantities can have nicotine-type effects. Signs and symptoms of toxicity include:
- Gastrointestinal symptoms, including nausea, vomiting, diarrhea; symptoms may be delayed 8 to 10 hours, up to 24 hours. Diarrhea may last 3 to 6 days.
- With large quantities, drowsiness, sweating, dilated pupils, and changes in blood pressure and heart rate
Jimson weed and belladonna (deadly nightshade) contain hyoscyamine (atropine) and scopolamine, which cause anticholinergic syndrome. Signs and symptoms include:
- Rapid heart rate
- Urinary retention
- Warm, dry skin
Castor beans contain ricin, a very toxic substance that’s released when the bean is chewed. The highly concentrated ricin released from a single chewed bean can be fatal in a child. Signs and symptoms of castor bean poisoning include:
- Diarrhea, which may be bloody
Other plant poisoning signs and symptoms include:
- Difficulty breathing
- Stomachache or nausea
Serious symptoms that might indicate a life-threatening condition
In some cases, plant poisoning can be fatal. In addition to calling Poison Control at 1-800-222-1222, seek immediate medical care (call 911) if you, or someone you are with, have ingested plants or plant products known or suspected of being poisonous and develop any of these life-threatening symptoms including:
- Altered mental status, including delirium or loss of consciousness
- Difficulty breathing
- Irregular heart rhythm
- Severe weakness or paralysis
What causes plant poisonings?
Plant poisonings are caused by ingesting or touching plants that contain highly toxic chemical substances. Plant poisonings are different from hypersensitivity, intolerance, and allergic reactions to plants. The toxic substances in plants disrupt or activate certain body systems. The most toxic plants contain substances that affect the central and peripheral nervous systems and/or heart, with downstream effects on the rest of the body.
The entire plant or part of the plant, such as the fruits, berries, leaves, stems, or roots of the plant may contain the toxic substance. For example, drinking tea brewed from the leaves of azaleas can cause poisoning, as can consuming honey from the nectar.
Most plant poisonings are accidental and can occur as children explore their environment. Other causes of plant poisonings include:
- Drinking tea brewed from the leaves of poisonous plants
- Eating cigarettes
- Eating plants or mushrooms thought to be safe
- Eating flowers, stems, berries or seeds from a poisonous plant
- Inhaling smoke from burning poisonous plants
- Preparing honey from poisonous plants
- Substance abuse, such as ingesting or smoking a plant as a hallucinogen
- Touching the leaves of poisonous plants
What are the risk factors for plant poisonings?
In general, plant poisonings in the United States involve young children who have accidentally ingested a small quantity of a poisonous plant. In adults, plant poisoning is more likely to occur from deliberate ingestion of a known poisonous plant (for self-harm or substance abuse) or from eating a plant thought to be edible.
Risk factors for accidental plant poisonings include:
- Young age, particularly under 5 years of age
- Recreating or working in an area with poisonous plants, such as poison ivy
- Foraging edible plants, such as wild mushrooms
- Substance abuse
The frequency of plant poisonings has been declining, based on reports to U.S. poison centers. In 1983, the percentage of poisonings from plants was 8.9%, compared with 6.0% in 1990, 4.9% in 2000, and 2.4% in 2009. From 2000 through 2009, there were 668,111 plant poisonings reported to U.S. poison centers. About 80% of plant poisonings were in children 5 and younger; nearly 58% were in children 1 and younger. Of 45 plant poisoning fatalities reported from 1983 through 2009, Datura species (e.g., jimson weed) and Cicuta species (e.g., water hemlock) were responsible for about 35% of them.
Reducing your risk of plant poisoning
Fortunately, plants that cause the most serious symptoms—including jimson weed, oleander, water hemlock, and castor bean—are not common.
To reduce your child’s risk of plant poisoning:
- Learn the names of your indoor and outdoor plants and those growing naturally in your yard. Keep the information near your emergency phone numbers. If someone eats a plant, Poison Control needs to know what it is.
- Keep indoor plants out of reach of children.
- Supervise young children when they play outdoors, especially in wild areas.
To reduce your risk of plant poisoning:
- Find out if you are working or recreating in an area known to have poisonous plants, including plants with poisonous oils that can get on your clothes or skin.
- Only eat wild plants, including mushrooms if you know without a doubt what they are and they are safe to eat.
- Wear long pants and long-sleeved shirts in areas with poisonous plants.
- Do not burn plants that may contain tobacco, poison ivy, oak or sumac, due to the risk of inhalation poisoning
How are plant poisonings treated?
Most cases of plant poisoning are not serious, do not cause lasting harm, and do not require treatment. However, this does not mean you should wait for symptoms to appear. Some plant toxins, even life-threatening ones, can cause a delayed reaction. Or, the plant causes an initial gastrointestinal upset, followed later by serious neurotoxic symptoms and death.
Always call Poison Control at 1-800-222-1222 if you or a loved one has consumed a plant or plant product that is potentially poisonous, which includes wild mushrooms.
Plant poisoning treatment depends on the plant, the dose, and the signs and symptoms of the patient. In an emergency setting, the physician will consult with the poison center for help with plant identification.
Hospital treatment for severe plant poisonings may include:
- Activated charcoal to prevent the body from absorbing the toxin; this treatment is most useful soon after ingestion
- Antidotes for the plant toxin. These counteracting drugs are available for cholinergic, anticholinergic, and cardiac glycoside plant poisonings.
- Heart medicine to restore a normal heart rhythm
- Mechanical ventilation for patients who can’t breathe on their own
- Seizure control, such as with diazepam or phenobarbital
- Supportive care, such as dialysis for kidney failure
At-home treatment of plant poisoning
First aid for ingesting a poisonous plant may include drinking water or milk, if the person is awake and able to swallow. Call the Poison Center for next steps.
First aid for skin symptoms of poisonous plants, such as poison ivy, includes:
- Immediately rinsing the skin with rubbing alcohol or dishwashing soap and water. If you do not have access to these items, rinse with water for 15 minutes.
- Oatmeal baths for itchiness
- Medications, including prescription steroids, over-the-counter oral antihistamines, cortisone creams, and calamine lotion