9. Also known as Sowbread, the Cyclamen is a common household flowering plant with poisonous properties (i.e., terpenoids) to dogs. It can cause oral irritation, vomiting, diarrhea, heart abnormalities, seizures and death.ts cardiac glycosides, similar to digoxin, are very toxic to dogs and can cause fatal heart abnormalities, muscle tremors, incoordination, vomiting and bloody diarrhea. Also known as Sowbread, the Cyclamen is a common household flowering plant with poisonous properties (i.e., terpenoids) to dogs.