Common Hogweed Toxic?

Updated 2026-03-06| 4 min read| 1,981 found this helpful

Furanocoumarins in the plant cause phototoxic effects when skin contact is followed by sunlight exposure

Stem sap is the most toxic part, while leaves of subspecies sphondylium and sibircum are generally non-phototoxic

Contact toxicity to animals is very low, but ingestion or contact may cause adverse reactions in sensitive species

FAQ

Is Common Hogweed toxic to Humans?

Phototoxic dermatitis, skin redness, blistering, and possible long-term pigmentation changes after contact with sap followed by sun exposure (Moderate)

Is Common Hogweed toxic to Cats?

No specific recorded symptoms, potential mild skin irritation or phototoxic reactions after contact with toxic sap and sun exposure (Low)

Is Common Hogweed toxic to Dogs?

Phototoxic reactions observed, potential skin redness, dermatitis or blistering after contact with sap and subsequent sun exposure (Low)

Is Common Hogweed toxic to Horses?

No specific recorded symptoms, potential phototoxic skin reactions if exposed to sap followed by direct sunlight (Low)

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Toxicity Details

Humans

Moderate

Phototoxic dermatitis, skin redness, blistering, and possible long-term pigmentation changes after contact with sap followed by sun exposure

Cats

Low

No specific recorded symptoms, potential mild skin irritation or phototoxic reactions after contact with toxic sap and sun exposure

Dogs

Low

Phototoxic reactions observed, potential skin redness, dermatitis or blistering after contact with sap and subsequent sun exposure

Horses

Low

No specific recorded symptoms, potential phototoxic skin reactions if exposed to sap followed by direct sunlight

Toxicity Snapshot

Toxic PartsPrimarily stem sap; leaves of subspecies sphondylium and sibircum are generally non-phototoxic, with variable toxicity observed in subspecies granatense and ternatum

Exposure RouteDirect skin contact with toxic sap, ingestion of plant parts

Toxic CompoundsBergapten; Xanthotoxin; Psoralen; Imperatorin; Angelicin; Isopimpinellin; Peucedanin; Oxypeucedanin; Ostruthol; Isoimperatorin; Pimpinellin; Isobergapten; Marmesin; Phellopterin; Sphondin; Apterin; Archangelin

First Aid & Prevention

First 30 Minutes

• Immediately wash affected skin/contact areas with plenty of soap and cold water to remove residual plant sap
• Keep the exposed area fully covered and away from direct sunlight for at least 48 hours to prevent phototoxic reactions
• If ingested, rinse mouth thoroughly with clean water, do not induce vomiting unless instructed by a medical/vet professional

Contact Vet Immediately

• Your pet develops skin blistering, redness, or ulceration after contact with the plant
• Your pet shows signs of stomatitis, difficulty eating, or abnormal behavior after ingesting plant parts
• Symptoms like skin irritation, eye redness, or swelling persist for more than 24 hours after first aid

Prevention

• Keep pets and livestock away from areas where common hogweed grows, especially during sunny weather
• Wear protective gloves, long sleeves and goggles when handling the plant to avoid contact with sap
• Never feed any parts of the plant to pets, poultry or livestock

Treatment & Prognosis

• Apply topical antibiotic and glucocorticoid ointments to affected skin areas as prescribed
• Administer analgesics to relieve pain caused by phototoxic reactions or mucosal ulcerations
• Strictly avoid sunlight exposure of the affected area until all symptoms fully resolve

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Professional Toxicology

Scientific NameHeracleum sphondylium L.s.l.

AliasesHogweed、Wiesen-Bärenklau (German)、Patte d'ours (French)、Panace commune (Italian)

Toxicity Grade

HumansModerate

CatsLow

DogsLow

HorsesLow

Target Organs

SkinOral mucosaDigestive tract

Mechanism of Action

• Furanocoumarins react with UV radiation from sunlight after skin contact, causing oxidative damage to skin cells and phototoxic reactions

• Ingestion of plant parts may cause direct irritation and ulceration of the oral and gastrointestinal mucosa in sensitive species

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Cattle: Phototoxic skin reactions observed after exposure to sap and sunlight

Sheep: Phototoxic skin reactions observed after exposure to sap and sunlight

Goats: Ulcerative stomatitis reported after ingestion of related giant hogweed, potential phototoxic reactions

Poultry: Phototoxic effects observed; ducklings develop contact dermatitis on unpigmented beaks after exposure

Confusion Risk

The following plants look similar and may be confused:

Giant Hogweed Heracleum mantegazzianum

Visually similar with same umbel flower structure, but giant hogweed is much larger and has significantly higher furanocoumarin content and stronger toxicity

Rough Chervil Chaerophyllum temulum

Belongs to the same Apiaceae family, has similar feathery leaves and small white umbel flowers; rough chervil is neurotoxic even without sunlight exposure

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Related Toxic Plants

Poison Hemlock

Conium maculatum

High toxicity, fatal to humans and animals even in small ingestion amounts

Water Hemlock

Cicuta maculata

Severe toxicity, one of the most toxic plants native to North America, causes fatal seizures

Giant Hogweed

Heracleum mantegazzianum

High toxicity, causes severe blistering and permanent skin scarring on contact with sap

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Data Sources

1. CliniTox (Universität Zürich)

This information is for reference only and does not constitute medical advice. If ingestion or poisoning is suspected, seek medical or veterinary attention immediately.