Viper's Bugloss Toxic?

Updated 2026-03-06| 5 min read| 3,220 found this helpful

Echium vulgare

Toxic to horses due to pyrrolizidine alkaloid content; toxicity to cats and dogs has not been verified to date

Liver damage in horses only occurs after ingestion of large quantities or long-term repeated exposure to the plant

All parts of the plant are toxic, with total pyrrolizidine alkaloid content ranging between 0.14% and 0.25%

FAQ

Is Viper's Bugloss toxic to Humans?

No confirmed human toxicity data available; ingestion may potentially cause gastrointestinal irritation and cumulative liver damage with repeated exposure (Low)

Is Viper's Bugloss toxic to Cats?

Toxicity and associated clinical symptoms are currently unknown (Unknown)

Is Viper's Bugloss toxic to Dogs?

Toxicity and associated clinical symptoms are currently unknown (Unknown)

Is Viper's Bugloss toxic to Horses?

Acute large ingestion may cause gastrointestinal mucosal irritation; chronic exposure leads to liver damage, weight loss and progressive liver disease (Moderate)

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Toxicity Details

Humans

Low

No confirmed human toxicity data available; ingestion may potentially cause gastrointestinal irritation and cumulative liver damage with repeated exposure

Cats

Unknown

Toxicity and associated clinical symptoms are currently unknown

Dogs

Unknown

Toxicity and associated clinical symptoms are currently unknown

Horses

Moderate

Acute large ingestion may cause gastrointestinal mucosal irritation; chronic exposure leads to liver damage, weight loss and progressive liver disease

Toxicity Snapshot

Toxic PartsAll parts of the plant are toxic

Exposure RouteIngestion is the only confirmed exposure route; contact with broken plant material may cause minor skin irritation in sensitive individuals

Toxic CompoundsEchinatin; Lycopsamin; Heliosupin; 12-Acetylheliosupin; Asperumin; Pyrrolizidine alkaloids

First Aid & Prevention

First 30 Minutes

• Remove all remaining plant material from the exposed animal's access and mouth immediately
• Induce vomiting and administer activated charcoal for pet ingestion only if explicitly directed by a veterinarian
• Collect a sample of the ingested plant for formal identification to guide targeted treatment

Contact Vet Immediately

• Any confirmed or suspected ingestion of the plant by horses, even if no symptoms are immediately visible
• Appearance of gastrointestinal distress, lethargy, or unexplained weight loss in animals with access to this plant
• Confirmed repeated exposure to the plant over days or weeks for any animal species

Prevention

• Remove all Viper's Bugloss plants from pastures, grazing areas, and yards accessible to horses and other livestock
• Avoid feeding hay or forage contaminated with this plant to horses or other herbivorous animals
• Restrict pet access to areas where this plant grows in high density to prevent accidental ingestion

Treatment & Prognosis

• Perform gastrointestinal decontamination (emesis, activated charcoal, cathartics) as appropriate for the species and time since ingestion
• Provide supportive care including liver protectants, fluid therapy, and nutritional support for cases with confirmed liver damage
• Monitor liver function regularly for several weeks following confirmed exposure to catch progressive damage early

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Professional Toxicology

Scientific NameEchium vulgare

AliasesCommon Viper's Head、Common Adder's Head、Blue Ox Tongue、Blue Henry、Sky Fire、Stiff Little Hans、Proud Henry、Common Viperine、Blue Viper's Herb

Toxicity Grade

HumansLow

CatsUnknown

DogsUnknown

HorsesModerate

Target Organs

LiverGastrointestinal tract

Mechanism of Action

• Pyrrolizidine alkaloids are metabolized in the liver to reactive toxic intermediates that damage hepatocytes

• Toxicity is cumulative, with repeated small exposures leading to progressive liver injury over time

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Cattle: Suspected to be at risk of liver damage from prolonged ingestion, similar to horses

Sheep: Higher resistance to pyrrolizidine alkaloid toxicity than horses, but long-term high intake still causes liver injury

Goats: Moderate resistance to toxicity, but repeated high exposure can lead to cumulative liver damage

Confusion Risk

The following plants look similar and may be confused:

Lungwort Pulmonaria sp.

Visually similar due to shared blue-purple clustered flower morphology; Lungwort has distinct spotted leaves absent on Viper's Bugloss, and is also toxic if ingested

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Related Toxic Plants

Common Comfrey

Symphytum officinale

Moderately toxic, contains pyrrolizidine alkaloids that cause liver damage

Hound's Tongue

Cynoglossum officinale

Moderately toxic, causes liver injury and neurological symptoms in livestock

Green Alkanet

Pentaglottis sempervirens

Low to moderately toxic, contains pyrrolizidine alkaloids that pose risk with repeated ingestion

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Data Sources

1. ASPCA Animal Poison Control

2. 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.

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