Is California Buckeye safe for cats and dogs?
| Species | Verdict |
|---|---|
| Cats | Toxic |
| Dogs | Toxic |
Severity: Severe
Read the full first-aid guide: what to do if your pet ate something toxic
California buckeye is one of the state's most distinctive native trees - UC ANR's 'Real Dirt' garden blog calls it 'a true California native, found nowhere else in the world,' growing across the central coast ranges, the Sierra Nevada and Cascade foothills, the Siskiyou Mountains, and into northern Los Angeles County, at elevations up to 4,000-5,500 feet. It is also widely used in California native-plant landscaping specifically because it is drought-deciduous, so exposure for a pet is as likely in a yard or park planting as in the wild.
ASPCA lists Buckeye (Aesculus spp., commonly known as Horse Chestnut) as toxic to dogs and cats: the toxic principle is aesculin, a glycosidic saponin, along with other saponins, and clinical signs include severe vomiting and diarrhea, depression or excitement, dilated pupils, coma, convulsions, and a wobbly, uncoordinated gait. UC ANR's coverage of the California species specifically confirms the same toxin (aesculin) is present in all plant parts, with the seeds particularly toxic - a defense that normally protects the tree from grazing animals, even though squirrels can eat the nuts and ruminants tolerate very young shoots. If a dog or cat has chewed on buckeye seeds, bark, or leaves and shows vomiting, disorientation, or any neurological signs, call ASPCA Animal Poison Control (888-426-4435) or Pet Poison Helpline (855-764-7661) and get to a vet - coma and convulsions are on the documented symptom list, not a worst-case guess.
Facts and examples
- California buckeye is a true California native found nowhere else in the world, growing in the central coast ranges, the Sierra Nevada and Cascade foothills, the Siskiyou Mountains, and northern Los Angeles County, at elevations up to 4,000-5,500 feet. (source, verified 2026-07-29)
- All parts of California buckeye contain the neurotoxic glycoside aesculin; the seeds are toxic, which normally protects the tree from grazing animals, though squirrels can eat the nuts and ruminants can tolerate very young shoots. (source, verified 2026-07-29)
- ASPCA lists Buckeye (Aesculus spp., common name Horse Chestnut) as toxic to dogs and cats, toxic principle aesculin (a glycosidic saponin) and other saponins, clinical signs severe vomiting and diarrhea, depression or excitement, dilated pupils, coma, convulsions, and wobbliness. (source, verified 2026-07-29)
Verdict re-verified against aspca.org, 2026-07-29 — confirmed unchanged. Source
This page is for general information only and is not veterinary advice, diagnosis, or treatment. If your pet is showing symptoms, or you think they ate or touched something dangerous, contact your veterinarian or a pet poison-control hotline immediately.
Last verified 2026-07-29