Hydrangea

Hydrangea plants, beloved for their showy flowers, have a darker side. Several parts of the plant the buds, flowers and leaves contain a compound known as glycoside amygdalin. It’s the amygdalin that has the potential to make hydrangea poisonous, because it can break down (in several different ways) to produce cyanide. The same substance is found in peach and plum pits and apple and pear seeds.

People and pets, including horses, dogs and cats, can experience hydrangea poisoning. For hydrangea poisoning to occur, a person or pet must eat very large quantities of the leaves, buds and/or flowers. There is one recorded case of a horse eating a potted hydrangea and becoming seriously poisoned. Typically hydrangea poisoning produces severe gastroenteritis symptoms, along with diarrhea, which is frequently bloody.

The reason hydrangea flowers produce a euphoric feeling is because the amygdalin compound breaks down to produce cyanide-type effects in the cells in the body. Effectively, the cyanide deprives cells of oxygen. Most often hydrangea smokers report effects of dizziness, heart rate increases and euphoria, but if they smoke enough, the results can include intestinal and respiratory distress. It’s important to realize, though, that hydrogen cyanide is also present in cigarettes, so the potential to poison yourself with hydrangea, while present, is unlikely.