The Poison Garden at Alnwick Castle, in Northumberland (a northeast region of England) taught me about the chemical properties of many common plants. Here is a sample list from the notes I took.
The beautiful poppy flower is the source for opioid medications as well as the dangerous illegal drug heroine.
Willow tree bark contains salicylic acid, an ingredient of aspirin. This compound is a natural pain reliever, not a poison.
The Rhubarb leaf and about 3″ of the stem near the leaf contains oxalic acid, which in enough quantity can cause liver failure.
Laburnum has a pea-like berry. Four of them could kill a child. However, the entire plant is toxic.
Periwinkle lowers your blood pressure, and is now used to treat childhood leukemia.
The seed of berries of the Yew are toxic, yet are used in chemotherapy for breast cancer.
Giant hogweed, Heracleum, causes a horrible rash that can last up to four years when skin that has contacted the plant is exposed to sunlight.
The bitter honey of the common Rhododendron is poisonous.
Foxglove can give you heart palpitations if you handle it. All parts of the plant are poisonous, even deadly, if swallowed.
Break a laurel leaf and smell the almond scent at your own risk. You are inhaling cyanide, which prevents oxygen from bonding with your blood. People who trim laurel or handle the trimming must be careful.
Rosemary oil and Juniper berries? Avoid them while pregnant. They can cause miscarriage.
Did you learn anything new?