Tall Mahonia Toxic?

Updated 2026-03-06| 4 min read| 2,050 found this helpful

Tall Mahonia is classified as non-toxic to cats, dogs, and horses per official toxicology data

No documented severe toxic reactions are associated with normal intake of this plant by common companion animals

Excessive consumption may still cause mild, transient gastrointestinal upset in sensitive individuals, even though it is non-toxic

FAQ

Is Tall Mahonia toxic to Humans?

No confirmed severe toxicity reported; excessive ingestion may cause mild stomach pain, nausea, or loose stools in sensitive people (Non-toxic)

Is Tall Mahonia toxic to Cats?

No toxic symptoms expected; rare mild gastrointestinal irritation possible with extremely large intake (Non-toxic)

Is Tall Mahonia toxic to Dogs?

No toxic symptoms expected; rare mild gastrointestinal irritation possible with extremely large intake (Non-toxic)

Is Tall Mahonia toxic to Horses?

No toxic symptoms expected; rare mild gastrointestinal irritation possible with extremely large intake (Non-toxic)

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Toxicity Details

Humans

Non-toxic

No confirmed severe toxicity reported; excessive ingestion may cause mild stomach pain, nausea, or loose stools in sensitive people

Cats

Non-toxic

No toxic symptoms expected; rare mild gastrointestinal irritation possible with extremely large intake

Dogs

Non-toxic

No toxic symptoms expected; rare mild gastrointestinal irritation possible with extremely large intake

Horses

Non-toxic

No toxic symptoms expected; rare mild gastrointestinal irritation possible with extremely large intake

Toxicity Snapshot

Toxic PartsNo plant parts are considered toxic to cats, dogs, or horses; all parts have a low adverse risk profile for these species

Exposure RouteIngestion is the only relevant exposure route for mild adverse effects; skin contact does not trigger toxic reactions

Toxic CompoundsBerberine; Protoberberine alkaloids; Flavonoids

First Aid & Prevention

First 30 Minutes

• Wipe any remaining plant material from the mouth of the exposed animal or person
• Offer small amounts of fresh water to rinse the oral cavity
• Monitor for 1-2 hours for signs of mild gastrointestinal discomfort

Contact Vet Immediately

• If the individual exhibits persistent vomiting, diarrhea, or lethargy lasting longer than 2 hours
• If the amount ingested was extremely large (more than 10% of the animal's daily food intake)
• If the individual has pre-existing gastrointestinal or liver health conditions

Prevention

• Keep large quantities of pruned plant material out of reach of curious pets and young children
• Teach children not to eat unknown wild berries or plant parts to avoid misidentification risks
• Label plants in home gardens to prevent accidental confusion with toxic lookalike species

Treatment & Prognosis

• Provide supportive care only for mild gastrointestinal symptoms if they occur
• No specific antidote is required as the plant is non-toxic
• Consult a healthcare provider or veterinarian for persistent adverse effects

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Professional Toxicology

Scientific NameMahonia aquifolium

AliasesOregon Grape、Oregon Grape Holly、Mahonia Aguifolium、Holly-Leaved Berry、Mahonia

Toxicity Grade

HumansNon-toxic

CatsNon-toxic

DogsNon-toxic

HorsesNon-toxic

Target Organs

No specific organ toxicity reported

Mechanism of Action

• No toxic mechanism of action identified for studied species; alkaloid content is too low to cause adverse effects at normal ingestion volumes

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Sheep: No confirmed toxicity reported; expected low risk profile similar to horses

Goats: No confirmed toxicity reported; mild gastrointestinal upset possible with excessive intake

Rabbits: Non-toxic in small quantities; overconsumption may cause soft stool or mild digestive discomfort

Confusion Risk

The following plants look similar and may be confused:

American Holly Ilex opaca

Confusable due to shared sharp, glossy evergreen leaves; American Holly bears toxic bright red berries, while Tall Mahonia bears dark blue-purple clustered berries

European Holly Ilex aquifolium

Similar spiky leaf morphology leads to frequent misidentification; European Holly is moderately toxic to humans and pets, unlike non-toxic Tall Mahonia

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Related Toxic Plants

Mayapple

Podophyllum peltatum

High toxicity to humans, dogs, and horses

Blue Cohosh

Caulophyllum thalictroides

Moderate toxicity to humans and all companion animals

American Barberry

Berberis canadensis

Low to moderate toxicity if consumed in large quantities

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Data Sources

1. ASPCA Animal Poison Control

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