1. Oleander — One of the most poisonous plants in the world; all parts contain numerous toxins and ingestion can cause death.
2. Aloe vera — Use only the clear gel for medicinal uses; the yellow juice contains aloe-emodin, which can cause contact dermatitis.
3. Angel's trumpet — All parts contain atropine, hyoscine and hyoscyamine, which can cause hallucination, elevated temperature and death.
4. Elephant ears — All parts contain calcium oxalate, which can cause blisters, difficulty swallowing and swelling of the mouth and throat.
5. Chrysanthemum — Leaves and stalks contain arteglasin-A, which can cause contact dermatitis.
6. Poinsettias — Leaves, stems and sap contain an unknown toxin that can cause dermatitis and vomiting.
7. English ivy — Leaves contain didehydrofalcarinol, falcarinol and hederasaponins, which can cause difficulty in breathing, convulsions, vomiting, paralysis and coma.
8. Hydrangea — Leaves and bulbs contain hydragin, which can cause dermatitis, vomiting, abdominal pains, diarrhea, labored breathing, lethargy and coma.
9. Philodendron — Leaves and immature fruit contain calcium oxalate.
10. Azalea — All parts contain andromedotoxins, which can cause excessive salivation and perspiration, vomiting, dizziness, weakness, low blood pressure and other ailments.
11. Amaryllis — The bulb contains lycorine, which can cause vomiting, diarrhea and convulsions.
12. Dieffenbachia (Mother-in-law's tongue) — All parts contain calcium oxalate.