Horse Chestnut Toxic?

Updated 2026-03-06| 5 min read| 2,526 found this helpful

All Aesculus species are toxic, with Aesculus hippocastanum being the most toxic member of the genus.

Highest toxin concentrations are found in unripe fruits, fresh shoots, green fruit husks and flower honey.

Severe exposure can lead to neurological deficits and kidney failure, which carry a poor clinical prognosis.

FAQ

Is Horse Chestnut toxic to Humans?

Oral irritation, vomiting, diarrhea, colic, edema, low blood pressure; high/repeated ingestion causes neurological depression, deficits, and potential kidney failure. Latency is 1-3 hours, recovery typically takes 72-96 hours for non-severe cases. (High)

Is Horse Chestnut toxic to Cats?

No species-specific clinical data available; expected to exhibit similar gastrointestinal, neurological and renal symptoms as other mammals if ingested. (High)

Is Horse Chestnut toxic to Dogs?

No species-specific clinical data available; expected to exhibit similar gastrointestinal, neurological and renal symptoms as other mammals if ingested. (High)

Is Horse Chestnut toxic to Horses?

No species-specific clinical data available; expected to exhibit similar gastrointestinal, neurological and renal symptoms as other mammals if ingested. (High)

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Toxicity Details

Humans

High

Cats

High

No species-specific clinical data available; expected to exhibit similar gastrointestinal, neurological and renal symptoms as other mammals if ingested.

Dogs

High

No species-specific clinical data available; expected to exhibit similar gastrointestinal, neurological and renal symptoms as other mammals if ingested.

Horses

High

No species-specific clinical data available; expected to exhibit similar gastrointestinal, neurological and renal symptoms as other mammals if ingested.

Toxicity Snapshot

Toxic PartsAll plant parts, especially unripe fruits, fresh shoots, green fruit husks, and flower honey

Exposure RouteIngestion of any plant material, consumption of contaminated horse chestnut flower honey

Toxic CompoundsTriterpene saponins; Aescin (mixture of 30 glycosides including Aescin Ia, Ib, IIa, IIIa, IIIb, IV, V, VI); Isoaescin Ia, Ib, V; β-aescin; α-aescin; Cryptoaescin

First Aid & Prevention

First 30 Minutes

• Induce vomiting only if ingestion occurred within 2 hours and the exposed individual is fully conscious
• Administer activated charcoal to bind unabsorbed remaining toxins
• Thoroughly rinse the mouth with clean water to remove residual plant material
• Keep the individual calm and restrict strenuous activity to avoid worsening cardiovascular symptoms

Contact Vet Immediately

• Any confirmed or suspected ingestion of horse chestnut plant material or related honey
• Onset of vomiting, diarrhea, abdominal pain, swelling or lethargy post-exposure
• Appearance of neurological symptoms including disorientation, muscle weakness or reduced responsiveness
• Signs of reduced or absent urination indicating potential kidney damage

Prevention

• Keep fallen horse chestnut fruits, husks and plant clippings out of reach of children and pets
• Avoid consuming unprocessed horse chestnut products or honey sourced from dense horse chestnut growing regions
• Learn to distinguish horse chestnut from edible sweet chestnuts to prevent misidentification during foraging

Treatment & Prognosis

• Gastrointestinal decontamination via emesis, activated charcoal or gastric lavage as clinically appropriate
• Supportive fluid therapy to correct electrolyte imbalances and support kidney function
• Continuous monitoring of kidney function, blood pressure and neurological status for at least 96 hours post-exposure
• Targeted management of specific symptoms including colic, edema and neurological deficits

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Professional Toxicology

Scientific NameAesculus hippocastanum L.; Synonyms: Hippocastanum aesculus Cav., Hippocastanum vulgare Gaertn.

AliasesBuckeye、Common horse chestnut、Conker、Conker tree、Horse-chestnut、Spanish chestnut、White chestnut

Toxicity Grade

HumansHigh

CatsHigh

DogsHigh

HorsesHigh

Target Organs

Gastrointestinal tractKidneysCentral nervous systemCardiovascular systemRed blood cells

Mechanism of Action

• Aescin saponins irritate gastrointestinal mucosa, exert hemolytic effects on red blood cells, reduce blood pressure, and cause damage to nervous system and renal tissues

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Ruminants (cattle, sheep, goats): Exhibit longer symptom latency of 12-18 hours, with peak symptoms at 24-28 hours post-ingestion; neurological deficits may take 2 weeks to 18 months to fully resolve

Small mammals (rabbits, guinea pigs): No species-specific clinical data available; expected to develop severe gastrointestinal and systemic symptoms if large quantities are ingested

Confusion Risk

The following plants look similar and may be confused:

Red Buckeye Aesculus pavia

Belongs to the same Aesculus genus, is similarly highly toxic, and is often grown as an ornamental landscaping plant

Red Horse Chestnut Aesculus carnea

Visually similar to common horse chestnut, but has distinct red flowers and thornless leaves, and is also highly toxic

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Related Toxic Plants

Ohio Buckeye

Aesculus glabra

Highly toxic

Goldenrain Tree

Koelreuteria paniculata

Moderately toxic

Western Soapberry

Sapindus drummondii

Moderately toxic

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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.