Yes, Metallic Leaf Begonia is toxic to dogs!
Dogs accidentally consuming the Metallic Leaf Begonia 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).
Metallic Leaf Begonia consumption is also toxic to Cats and Horses.
Toxic Principles Of Metallic Leaf Begonia: Soluble calcium oxalates.
More Info About The Metallic Leaf Begonia Plant
Scientific Name: Begonia metallica
Family: Begoniaceae.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.