Yes, Spindle Tree is toxic to dogs!
Dogs accidentally consuming the Spindle Tree plants can show the following clinical symptoms: Vomiting, Prolonged Depression, Incoordination, Hypersalivaton, Sleepiness Or Excitation, Dilated Pupils, Low Body Temperature, Low Blood Pressure, Coma, Seizure And Death (In Rare Cases).
Spindle Tree consumption is also toxic to Cats and Horses.
Toxic Principles Of Spindle Tree: Alkaloids, Cardenolides.
More Info About The Spindle Tree Plant
Scientific Name: Euonymus atropurpurea
Family: Celastraceae.
Also known as: Wahoo, Burning Bush.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.