Lilies are some of the most poisonous plants to dogs. All parts of the lily plant, including the leaves, flowers, and stems, can be toxic to dogs.

Azaleas and rhododendrons are also poisonous to dogs. The leaves, flowers, and stems of these plants can all cause poisoning.

Tulip bulbs are poisonous to dogs. If your dog ingests a tulip bulb, it can cause vomiting, diarrhea, and even death.

Iris is another poisonous plant to dogs. All parts of the iris plant, including the leaves, flowers, and roots, can cause poisoning.

Oleander is a highly poisonous plant to dogs. All parts of the oleander plant, including the leaves, flowers, and stems, can cause poisoning.

Yews are poisonous to dogs. All parts of the yew plant, including the leaves, berries, and bark, can cause poisoning.

The leaves, stems, and green tomatoes of the tomato plant are poisonous to dogs. However, ripe tomatoes are not poisonous.