Yes, Giant Dracaena is toxic to dogs!
Dogs accidentally consuming the Giant Dracaena 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).
Giant Dracaena consumption is also toxic to Cats and Horses.
Toxic Principles Of Giant Dracaena: Saponins.
More Info About The Giant Dracaena Plant
Scientific Name: Cordyline australis
Family: Agavaceae.
Also known as: Palm Lily, Grass Palm.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.