Silver ragwort Toxic?

Updated 2026-03-06| 3 min read| 3,771 found this helpful

Pyrrolizidine alkaloid toxins remain fully active in dried hay, silage, and even after cooking, so contaminated feed remains dangerous long term.

No curative treatment exists for confirmed poisoning; immediate removal of all contaminated feed is the only critical intervention.

Pigs, horses, cattle, and chickens are the most sensitive exposed species, while sheep and goats have relatively higher tolerance to toxins.

FAQ

Is Silver ragwort toxic to Humans?

No specific clinical symptom data is available for humans; monitor for signs of liver damage (jaundice, abdominal pain, fatigue) if ingestion is suspected. (High)

Is Silver ragwort toxic to Cats?

No specific clinical symptom data is available for cats; monitor for lethargy, loss of appetite, and jaundice if ingestion is confirmed. (High)

Is Silver ragwort toxic to Dogs?

No specific clinical symptom data is available for dogs; monitor for weakness, reduced feed intake, and jaundice if ingestion is confirmed. (High)

Is Silver ragwort toxic to Horses?

May develop seneciosis (Schweinsberger disease); first chronic symptoms appear 3 days to 6 months post-ingestion, with a rapidly progressive terminal stage that is almost always fatal. (Severe)

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Toxicity Details

Humans

High

No specific clinical symptom data is available for humans; monitor for signs of liver damage (jaundice, abdominal pain, fatigue) if ingestion is suspected.

Cats

High

No specific clinical symptom data is available for cats; monitor for lethargy, loss of appetite, and jaundice if ingestion is confirmed.

Dogs

High

No specific clinical symptom data is available for dogs; monitor for weakness, reduced feed intake, and jaundice if ingestion is confirmed.

Horses

Severe

May develop seneciosis (Schweinsberger disease); first chronic symptoms appear 3 days to 6 months post-ingestion, with a rapidly progressive terminal stage that is almost always fatal.

Toxicity Snapshot

Toxic PartsEntire plant, all tissues are toxic

Exposure RouteIngestion of fresh plant material, or consumption of hay, silage, or processed feed contaminated with silver ragwort tissues

Toxic CompoundsPyrrolizidine alkaloids (jacobin, jaconin, jacodin, senecionine, retrorsine, seneciphylline, senkirkin, and related derivatives); Oxalates

First Aid & Prevention

First 30 Minutes

• Immediately remove all access to the plant or potentially contaminated feed sources.
• Collect a sample of the suspected ingested plant for formal identification if possible.
• Closely monitor the exposed individual for signs of lethargy, reduced appetite, or jaundice.

Contact Vet Immediately

• If ingestion of any quantity of silver ragwort is confirmed in pets or livestock.
• If signs of weakness, jaundice, neurological changes, or sudden weight loss appear post-exposure.
• If exposure occurs in high-sensitivity species including horses, pigs, cattle, or chickens.

Prevention

• Inspect all pasture, hay, and silage for silver ragwort presence before feeding to livestock.
• Avoid planting silver ragwort in gardens or grazing areas accessible to pets or farm animals.
• Train animal caretakers to identify silver ragwort and other toxic Senecio species to avoid accidental exposure.

Treatment & Prognosis

• No curative treatment exists for silver ragwort poisoning.
• Immediately cease all access to feed containing pyrrolizidine alkaloids to prevent further toxin accumulation.
• Administer veterinarian-directed supportive care to reduce liver damage symptoms and improve quality of life.

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Professional Toxicology

Scientific NameJacobaea maritima (L.) Pelser & Meijden

AliasesSenecio bicolor (Willd.) Tod.、Senecio cineraria DC.、Senecio bicolor (Willd.) Tod. subsp. cineraria (DC.) Chater

Toxicity Grade

HumansHigh

CatsHigh

DogsHigh

HorsesSevere

Target Organs

LiverKidneys

Mechanism of Action

• Pyrrolizidine alkaloids are metabolized in the liver into reactive intermediates that cause irreversible liver cell necrosis and scarring.

• Toxins are cumulative, so repeated low-level exposure leads to progressive chronic liver failure over weeks to months.

• Oxalate compounds may contribute to mild kidney irritation in cases of high-volume exposure.

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Pig: Highest sensitivity (toxicity index = 1); small exposure quantities can lead to rapidly fatal liver damage.

Chicken: Very high sensitivity (toxicity index = 5); exposure leads to fatal seneciosis.

Cattle: High sensitivity (toxicity index = 14); chronic exposure causes progressive irreversible liver failure.

Rat: Moderate sensitivity (toxicity index = 50); requires higher exposure doses to cause clinical poisoning.

Mouse: Low sensitivity (toxicity index = 150); tolerant to low levels of exposure.

Sheep, Goat: Lowest sensitivity (toxicity index = 200); can tolerate low repeated exposure, but high doses still cause liver damage.

Birds: Very severely toxic; even small exposure amounts lead to rapidly fatal poisoning.

Confusion Risk

The following plants look similar and may be confused:

Other ragwort species Other Senecio / Jacobaea spp.

Similar leaf and flower morphology; most species in these genera also contain toxic pyrrolizidine alkaloids, so misidentification carries high exposure risk.

St. John's wort Hypericum spp.

Some species share similar silvery-green foliage; St. John's wort is also toxic to livestock, causing photosensitivity reactions.

Rough hawksbeard Crepis biennis

Similar basal leaf rosette structure; this species is non-toxic, and can be distinguished by its lack of dense silvery felt-like leaf covering.

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Related Toxic Plants

Common ragwort

Jacobaea vulgaris

Severe (very highly toxic, causes fatal irreversible liver damage in all livestock species)

Common groundsel

Senecio vulgaris

High (toxic to pets and livestock, contains harmful pyrrolizidine alkaloids)

Tansy ragwort

Jacobaea erucifolia

Severe (very highly toxic, causes chronic progressive liver failure with even low repeated exposure)

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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.