Common comfrey Toxic?

Updated 2026-03-06| 2 min read| 1,077 found this helpful

All parts of common comfrey are toxic, containing dangerous pyrrolizidine alkaloid compounds

Chronic consumption leads to irreversible liver damage and associated loss of condition in exposed organisms

The plant is easily confused with other toxic Symphytum species and common hound's tongue

FAQ

Is Common comfrey toxic to Humans?

Chronic oral intake may cause liver damage, jaundice, unexplained weight loss, and reduced physical condition; large acute ingestions can cause mild gastrointestinal irritation (Low)

Is Common comfrey toxic to Cats?

No species-specific symptom data documented; chronic ingestion is expected to cause liver damage, lethargy, appetite loss, and condition loss consistent with pyrrolizidine alkaloid poisoning (Low)

Is Common comfrey toxic to Dogs?

No species-specific symptom data documented; chronic ingestion is expected to cause liver damage, lethargy, appetite loss, and condition loss consistent with pyrrolizidine alkaloid poisoning (Low)

Is Common comfrey toxic to Horses?

No species-specific symptom data documented; chronic ingestion is expected to cause liver damage, lethargy, appetite loss, and condition loss consistent with pyrrolizidine alkaloid poisoning (Low)

Not sure which plant? Snap a photo to ID in 1 secondGet App

Toxicity Details

Humans

Low

Chronic oral intake may cause liver damage, jaundice, unexplained weight loss, and reduced physical condition; large acute ingestions can cause mild gastrointestinal irritation

Cats

Low

No species-specific symptom data documented; chronic ingestion is expected to cause liver damage, lethargy, appetite loss, and condition loss consistent with pyrrolizidine alkaloid poisoning

Dogs

Low

No species-specific symptom data documented; chronic ingestion is expected to cause liver damage, lethargy, appetite loss, and condition loss consistent with pyrrolizidine alkaloid poisoning

Horses

Low

No species-specific symptom data documented; chronic ingestion is expected to cause liver damage, lethargy, appetite loss, and condition loss consistent with pyrrolizidine alkaloid poisoning

Toxicity Snapshot

Toxic PartsAll parts of the plant

Exposure RouteOral ingestion is the only confirmed toxic exposure route; casual dermal contact does not pose a measurable toxicity risk

Toxic CompoundsEchinatin; Lycopsamine; 7-Acetyllycopsamine; Heliosupine; Echimidine; Lasiocarpine; Viridiflorine; Symphytine; Intermedin; Europin; Symlandin; Other related pyrrolizidine alkaloids

First Aid & Prevention

First 30 Minutes

• Induce vomiting only if ingestion occurred within 2 hours and the affected individual is fully conscious and alert
• Administer activated charcoal to reduce absorption of remaining toxins in the gastrointestinal tract
• Remove all residual plant material from the mouth and surrounding area to prevent further intake

Contact Vet Immediately

• Any confirmed or suspected ingestion of common comfrey, even if no symptoms are immediately visible
• Development of jaundice, lethargy, unexplained weight loss, or appetite loss after potential exposure
• Accidental ingestion by vulnerable groups including small pets, young children, or pregnant animals/humans

Prevention

• Avoid planting common comfrey in areas accessible to pets, livestock, or young children
• Properly identify all foraged plants before consumption to avoid accidental intake of toxic lookalikes
• Do not use unregulated oral supplements containing comfrey, as they may contain harmful pyrrolizidine alkaloids

Treatment & Prognosis

• Gastrointestinal decontamination (emesis, activated charcoal, cathartics) as clinically appropriate for the exposure timeline
• Symptomatic and supportive care including liver protectants, fluid therapy, and nutritional support for liver injury
• Long-term liver function monitoring for 3-6 months post-exposure to detect chronic, progressive liver damage

Emergency? Open PlantFun for real-time AI guidanceGet App

Professional Toxicology

Scientific NameSymphytum officinale L.

AliasesTrue comfrey、Quaker comfrey、Consoude officinale、Consolida maggiore、Echte Wallwurz

Toxicity Grade

HumansLow

CatsLow

DogsLow

HorsesLow

Target Organs

Liver (primary target organ)Gastrointestinal tract (mild acute irritation with large ingestions)

Mechanism of Action

• Pyrrolizidine alkaloids are metabolized in the liver to reactive pyrrole intermediates that bind to cellular proteins and DNA, causing hepatocyte necrosis, fibrosis, and veno-occlusive disease with chronic repeated exposure

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Cattle: Chronic ingestion leads to liver damage, reduced growth rate, and decreased milk production

Sheep: Relatively more resistant to pyrrolizidine alkaloid toxicity than other livestock, but chronic intake still causes subclinical liver damage

Goats: Moderately resistant to pyrrolizidine alkaloids, but long-term repeated exposure leads to chronic liver injury and reduced productivity

Confusion Risk

The following plants look similar and may be confused:

Other Symphytum species Symphytum spp.

Closely related Symphytum species have near-identical visual morphology to common comfrey; all species in this genus are documented to contain toxic pyrrolizidine alkaloids

Common hound's tongue Cynoglossum officinale

This related Boraginaceae species has very similar leaf shape and growth habit to common comfrey; it is also toxic, containing the same class of harmful pyrrolizidine alkaloids

Use PlantFun to scan and avoid misidentificationGet App

Related Toxic Plants

Common hound's tongue

Cynoglossum officinale

Low to Moderate toxicity

European heliotrope

Heliotropium europaeum

Moderate to High toxicity

Viper's bugloss

Echium vulgare

Low toxicity

Download PlantFun App

Identify, grow and care for plants effectively!

Instant Plant ID

Take a photo to quickly identify plants.

Smart Care Reminders

Generate watering and care schedules.

Toxicity & Disease Diagnosis

Identify toxic plants and pests with treatment advice.

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.