Buckeye
Aesculus glabra
Hippocastanaceae
Buckeye; Ohio Buckeye; Horse Chestnut; Ohio Horse Chestnut; Fetid Buckeye; American Buckeye; Aesculus; Aesculus glabra
Aesculin, a glycosidic saponin; aescin or escin, a saponin mixture; other saponins; fraxin; and possibly alkaloids. All parts of the plant should be considered toxic, including seeds, nuts, leaves, bark, sprouts, and flowers.
Severe gastrointestinal upset, vomiting, diarrhea, abdominal pain, drooling, excessive thirst, reduced appetite, depression or excitement, hyperexcitability, dilated pupils, loss of coordination, wobbliness, ataxia, twitching, muscle stiffness, muscle spasms, tremors, weakness, seizures, convulsions, coma, and possible death in severe cases. Seeds or nuts may also pose a choking hazard or bowel-obstruction risk if swallowed whole.
Buckeye, Aesculus glabra, also known as Ohio Buckeye, Ohio Horse Chestnut, Fetid Buckeye, Horse Chestnut, and American Buckeye, is a toxic tree that can grow to heights of 50 feet or more. It is best known for its distinctive nut-like seeds, palmately compound leaves, and ornamental or shade-tree value. Although the seed may look somewhat like an edible chestnut to the casual observer, Buckeye and Horse Chestnut seeds are not edible chestnuts and should be treated as poisonous.
The plant has historically been placed in the family Hippocastanaceae, which is why older toxic plant references often list Buckeye under that family. More modern classifications commonly place Aesculus in Sapindaceae. For practical pet-safety purposes, the family-name change does not alter the toxicology: all parts of the tree should be considered toxic, including the seeds, nuts, leaves, bark, sprouts, flowers, and young growth.
The toxicity of Buckeye can be attributed to glycosidic saponins and related compounds, including aesculin, aescin or escin, other saponins, fraxin, and possibly alkaloids. ASPCA lists Buckeye, Aesculus spp., as toxic to dogs, cats, and horses, with aesculin and other saponins identified as toxic principles. ASPCA’s specific Horse Chestnut entry for Aesculus glabra likewise lists severe vomiting and diarrhea, depression or excitement, dilated pupils, weakness, unsteadiness, seizures, and coma as clinical signs.
In companion animals, puppies and young dogs that are allowed to roam freely in an area where seeds have dropped to the ground are among the highest-risk animals. The combination of a young dog’s curiosity, desire to explore the world with its mouth, willingness to chew or swallow unusual objects, and the inherent toxicity of the plant can make for a potentially dangerous exposure. Seeds or nuts may also create a mechanical problem if swallowed whole, because they can act as a choking hazard or contribute to bowel obstruction.
In more mature animals, overconsumption and acute toxicity resulting in serious side effects are less common. Not just the fruit, but also the leaves, bark, flowers, and sprouts possess a sharp, bitter, unpleasant taste that tends to limit the amount an animal can tolerate ingesting. Additionally, some of the main toxic compounds, including aesculin, are not absorbed especially well by the body, which helps explain why many exposures result primarily in gastrointestinal signs.
In the overwhelming majority of ordinary dog and cat exposures, severe gastroenteritis is the primary adverse reaction. This may include vomiting, diarrhea, abdominal pain, drooling, reduced appetite, lethargy, depression, and general gastrointestinal discomfort. However, as with any toxin, the larger the amount consumed, the more severe the clinical signs may become. It is possible, although uncommon, for animals to consume enough plant material to develop loss of coordination, muscle spasms, twitching, hyperexcitability, depression, muscle weakness, seizures, paralysis, unconsciousness, coma, or death.
The risk is also greater in horses and grazing animals because they may consume leaves, sprouts, or fallen seeds in quantity, especially where access is prolonged or desirable forage is limited. Current pet-poison references include horses among the species at risk, and signs may include colic, diarrhea, tremors, seizures, weakness, and severe systemic illness. Any horse or livestock exposure involving significant ingestion should be treated more seriously than a minor chew exposure in an otherwise stable dog.
Buckeye should therefore be treated as a genuinely toxic landscape and shade tree. The practical concern is greatest in the fall when seeds drop, after storms or pruning when leaves and branches are accessible, and in yards, parks, pastures, or fence lines where animals may chew fallen material. Preventing access to the seeds is especially important because they are visually interesting, easy for dogs to pick up, and may be both toxic and physically obstructive if swallowed.
Immediate Response to Buckeye Ingestion
- Remove the Source: Prevent further ingestion by removing the animal from the Buckeye tree, fallen seeds, nuts, leaves, sprouts, bark, flowers, branches, clippings, or any area containing accessible plant material.
- Remove Plant Material from the Mouth: If ingestion was recent and it is safe to do so, remove visible plant material, seed fragments, leaves, or bark from the mouth and flush the mouth thoroughly with water.
- Identify the Plant Part: Determine whether the animal chewed leaves, bark, flowers, sprouts, seeds, nuts, or swallowed a seed whole. Seed or nut ingestion is more concerning because it may involve both toxicity and obstruction risk.
- Watch for Early Signs: Monitor for vomiting, diarrhea, drooling, abdominal pain, reduced appetite, depression, excitement, dilated pupils, wobbliness, loss of coordination, twitching, tremors, muscle stiffness, or weakness.
- Watch for Severe Signs: Seizures, convulsions, collapse, coma, severe weakness, persistent vomiting, bloody diarrhea, inability to keep water down, or signs of obstruction should be treated as emergency signs.
- Contact Veterinary Help: Consult a veterinarian, emergency veterinary clinic, ASPCA Animal Poison Control, or Pet Poison Helpline if ingestion is suspected, if symptoms are present, if a seed or nut may have been swallowed whole, if the amount is unknown, or if the exposed animal is a cat, dog, horse, livestock animal, puppy, kitten, young animal, elderly animal, pregnant animal, or medically fragile animal.
Inducing Vomiting and Decontamination
- Getting Plant Material Out Matters: If a dog has recently swallowed Buckeye plant material, removing remaining material from the stomach may reduce continued exposure to aesculin, aescin, and other saponins. In appropriate dog exposures, vomiting may be one of the least disruptive ways to remove recently ingested leaves, bark, sprouts, or chewed seed material before more toxin is absorbed.
- Seed Obstruction Warning: If the dog swallowed a whole Buckeye seed or nut, contact a veterinarian or poison-control professional before attempting vomiting, because the seed may pose a choking or obstruction risk depending on size, shape, and the animal involved.
- Inducing Vomiting in Dogs Only: If ingestion was recent and the dog is alert, breathing normally, able to swallow, and not showing weakness, collapse, seizures, severe depression, repeated vomiting, respiratory distress, obstruction signs, or neurologic signs, a veterinarian or animal poison-control professional may recommend inducing vomiting with fresh 3% hydrogen peroxide.
- Cat Warning: Hydrogen peroxide should not be used to induce vomiting in cats unless a veterinarian specifically directs it. Cats are more prone to irritation and complications from hydrogen peroxide, and home vomiting attempts may create more risk than benefit.
- Do Not Induce Vomiting in an Unstable Animal: Vomiting should not be attempted in any animal that is weak, collapsed, sedated, having trouble breathing, unable to swallow normally, already vomiting repeatedly, seizing, showing neurologic signs, showing obstruction signs, or otherwise unstable.
- Activated Charcoal and Gastric Lavage: If a large quantity was ingested, or if the exposure is high-risk, a veterinarian may consider gastric lavage, activated charcoal, cathartics, anti-nausea medication, fluid therapy, or other decontamination and stabilization measures depending on the species, amount, timing, and clinical signs.
Dogs and Cats: Supportive Care
- Expected Signs: In many dog and cat exposures, signs are limited to gastrointestinal upset, including vomiting, diarrhea, abdominal discomfort, drooling, lethargy, or reduced appetite.
- Hydration: Ensure the pet receives adequate fluids to reduce the risk of dehydration from vomiting or diarrhea.
- Gastrointestinal Monitoring: Pets with persistent vomiting, persistent diarrhea, abdominal pain, blood in stool, refusal to eat, weakness, or inability to keep water down should be evaluated by a veterinarian.
- Obstruction Monitoring: If a seed or nut may have been swallowed whole, watch for repeated vomiting, abdominal pain, bloating, straining, lack of stool, refusal to eat, or worsening lethargy, as these may suggest obstruction.
Horses and Grazing Animals
- Higher-Risk Exposure: Horses and livestock may be at greater risk when they have access to fallen seeds, sprouts, leaves, branches, or large amounts of plant material in pasture or along fence lines.
- Serious Signs: Colic, diarrhea, severe depression or excitement, muscle twitching, weakness, loss of coordination, tremors, seizures, convulsions, collapse, or coma should be treated as emergency signs.
- Veterinary Care: Significant exposure in horses or livestock should be handled by a veterinarian, as treatment may require fluid therapy, gastrointestinal support, seizure control, monitoring, and other symptomatic care.
- Pasture Management: Remove fallen seeds, branches, leaves, and sprouts from areas where horses or livestock graze, and avoid planting Buckeye or Horse Chestnut trees where grazing animals can access fallen material.
Prognosis and Recovery
- Most Mild Cases: With swift diagnosis and treatment, nearly all animals with mild to moderate exposure are expected to survive without permanent damage.
- Variable Severity: Prognosis depends on the amount ingested, the plant part consumed, whether a seed was swallowed whole, the species and size of the animal, and whether neurologic signs develop.
- Higher-Risk Cases: Prognosis becomes more guarded if the animal develops seizures, coma, severe weakness, persistent gastrointestinal signs, respiratory compromise, obstruction, or severe neurologic signs.
- Prevention: Prevent further ingestion of the plant, remove fallen seeds and clippings, keep puppies and chewing-prone dogs away from Buckeye trees, and consult a veterinarian promptly when exposure is suspected.