These plants contains grayantoxin, which can cause a wide range of symptoms when dogs ingest it, such as vomiting, diarrhea, drooling, abnormal heart rate, tremors, and even comas.
Dogs that ingest cyclamen can experience symptoms such as drooling, vomiting, and diarrhea due to an ingredient by the name of terpenoid saponins.
Hellebore: As a result of the presence of toxic bufadienolides and glycosides, dogs that ingest this plant can experience gastrointestinal problems, drooling, colic, and depression.
Hydrangeas: These plants contain a substance by the name of cyanogenic glycoside, and if dogs ingest it, they can experience symptoms such as vomiting, diarrhea, and depression.