Why?
Black walnuts are highly toxic to dogs and contain juglone which causes neurological damage. English walnuts are less toxic but still dangerous due to high fat content and risk of mold.
How much can dogs have?
NONE of any walnut variety.
What to watch out for
Even English walnuts can be infected with mold producing tremorgenic mycotoxins. Symptoms include tremors, seizures, and neurological damage. Black walnuts are always a medical emergency.
🚨 If your dog ate walnuts: Contact your vet or the ASPCA Animal Poison Control Center at (888) 426-4435 right away. Don't wait for symptoms — many toxins act internally before signs appear.