Is Black Walnut 'Thomas' toxic to dogs?

Yes — black walnut 'thomas' is toxic to dogs according to the ASPCA. Keep it well away from any dog that chews plants; reactions can be significant. Black walnut (Juglans nigra) is listed by the ASPCA as toxic. Moldy nuts and hulls can produce tremorgenic mycotoxins such as penitrem A, causing tremors, seizures and incoordination in dogs; the roots, bark, wood, pollen and nuts are highly toxic to horses, triggering laminitis and colic, and even wood shavings are dangerous. Keep pets and horses away from fallen nuts, hulls and walnut bedding.

Black walnut (Juglans nigra) is listed by the ASPCA as toxic. Moldy nuts and hulls can produce tremorgenic mycotoxins such as penitrem A, causing tremors, seizures and incoordination in dogs; the roots, bark, wood, pollen and nuts are highly toxic to horses, triggering laminitis and colic, and even wood shavings are dangerous. Keep pets and horses away from fallen nuts, hulls and walnut bedding. Signs usually appear soon after chewing rather than hours later — watch for drooling, pawing at the mouth, vomiting, loss of appetite, or unusual lethargy after your dog has had access to black walnut 'thomas'.

Stay calm. Remove any plant from your dog's mouth and take the plant away. Note how much was eaten and when, and do not induce vomiting unless told to. Call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 and follow their advice; a leaf or photo helps the vet treat it correctly.

The ASPCA classification Growli uses applies to both cats and dogs: Black Walnut 'Thomas' is toxic to cats as well. See the full black walnut 'thomas' pet-safety guide for both species.

For a similar look without the risk, see the best dogs-safe plants list — every plant there is ASPCA non-toxic to cats and dogs.