Yes, Impala Lily is toxic to dogs!
Dogs accidentally consuming the Impala Lily 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).
Impala Lily consumption is also toxic to Cats.
Toxic Principles Of Impala Lily: Digitalis like glycosides.
More Info About The Impala Lily Plant
Scientific Name: Adenium obesum
Family: Apocynaceae.
Also known as: Desert Rose, Mock Azalea, Sabi Star, Desert Azalea, Kudu Lily.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.