Yarrow Toxic?

Updated 2026-03-06| 3 min read| 1,838 found this helpful

Yarrow is confirmed toxic to cats, dogs, and horses per ASPCA toxicology data.

Toxic active compounds include achillein (glycoalkaloid), monoterpenes, and achillin (sesquiterpene lactone).

Exposure via ingestion or skin contact can trigger gastrointestinal distress, dermatitis, and lethargy in susceptible animals.

FAQ

Is Yarrow toxic to Humans?

No confirmed acute human toxicity reported; mild skin irritation may occur with prolonged direct contact with fresh foliage. (Non-toxic)

Is Yarrow toxic to Cats?

Vomiting, diarrhea, colic, drooling, anorexia, dermatitis, depression (Low)

Is Yarrow toxic to Dogs?

Vomiting, diarrhea, colic, drooling, anorexia, dermatitis, depression (Low)

Is Yarrow toxic to Horses?

Vomiting, diarrhea, colic, drooling, anorexia, dermatitis, depression (Low)

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Toxicity Details

Humans

Non-toxic

No confirmed acute human toxicity reported; mild skin irritation may occur with prolonged direct contact with fresh foliage.

Cats

Low

Vomiting, diarrhea, colic, drooling, anorexia, dermatitis, depression

Dogs

Low

Vomiting, diarrhea, colic, drooling, anorexia, dermatitis, depression

Horses

Low

Vomiting, diarrhea, colic, drooling, anorexia, dermatitis, depression

Toxicity Snapshot

Toxic PartsAll above-ground plant parts (leaves, stems, flowers, fresh foliage) contain toxic compounds

Exposure RouteIngestion of plant material, direct skin contact with fresh plant sap or foliage

Toxic Compoundsglycoalkaloids (achillein); monoterpenes; sesquiterpene lactones (achillin)

First Aid & Prevention

First 30 Minutes

• Remove all remaining yarrow plant material from the animal's mouth, fur, skin, and immediate environment.
• Rinse affected skin areas with cool, soapy water if contact dermatitis is observed.
• Do not induce vomiting unless explicitly directed to do so by a licensed veterinarian.

Contact Vet Immediately

• If your cat, dog, or horse has ingested any quantity of yarrow plant material.
• If symptoms including vomiting, diarrhea, colic, drooling, or lethargy appear after exposure.
• If skin irritation persists for more than 1 hour after rinsing the affected area.

Prevention

• Remove all yarrow plants from yards, pastures, and other areas accessible to pets and grazing horses.
• Avoid feeding forage or hay that contains yarrow to cats, dogs, or horses.
• Wear protective gloves when handling wild or cultivated yarrow to avoid potential skin irritation.

Treatment & Prognosis

• Veterinary supportive care including fluid therapy to correct dehydration from vomiting and diarrhea.
• Administer veterinarian-prescribed anti-inflammatory medication to reduce gastrointestinal and skin irritation.
• Provide symptomatic care for colic or depression as directed by a licensed veterinary professional.

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Professional Toxicology

Scientific NameAchillea millefolium

AliasesMilfoil、Soldier's Woundwort、Dog Daisy Thousand Seal、Devil's Nettle、Old Man's Pepper

Toxicity Grade

HumansNon-toxic

CatsLow

DogsLow

HorsesLow

Target Organs

Gastrointestinal tractSkinCentral nervous system

Mechanism of Action

• Toxic compounds irritate the gastrointestinal mucosa, leading to vomiting, diarrhea, and abdominal pain.

• Volatile monoterpenes trigger inflammatory responses in skin, causing contact dermatitis.

• Glycoalkaloids may cause mild central nervous system depression in large enough doses.

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Cattle: Low toxicity risk; small amounts in forage are generally tolerated, large ingestion may cause mild digestive upset

Sheep: Low toxicity risk; similar to cattle, small quantities of yarrow in feed do not typically cause adverse effects

Small pet mammals (rabbits, guinea pigs): Moderate toxicity risk; ingestion may cause digestive distress, appetite loss, and lethargy

Confusion Risk

The following plants look similar and may be confused:

Other yarrow species Achillea spp.

Other species in the Achillea genus are visually similar to common yarrow, sharing characteristic feathery foliage and flat clusters of small white or pink flowers; most carry similar toxicity risks.

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Related Toxic Plants

Common Ragwort

Jacobaea vulgaris

High toxicity; causes irreversible liver damage in all grazing animals and pets if ingested

Garden Chrysanthemum

Chrysanthemum spp.

Low to moderate toxicity; causes gastrointestinal irritation and contact dermatitis in pets

Common Tansy

Tanacetum vulgare

Moderate toxicity; causes vomiting, seizures, and liver damage if ingested in large quantities

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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.