Yes, Sago Palm is toxic to dogs!
Dogs accidentally consuming the Sago Palm 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).
Sago Palm consumption is also toxic to Cats and Horses.
Toxic Principles Of Sago Palm: Cycasin.
More Info About The Sago Palm Plant
Scientific Name: Cycas revoluta, zamia species
Family: Cycadaceae.
Also known as: Coontie Palm, Cardboard Palm, cycads and zamias.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.