10. Rhubarb Leaves
Rhubarb stalks are used in pies, jams, and desserts, but rhubarb leaves are dangerously toxic. They contain oxalic acid and anthraquinone glycosides, which can cause kidney failure, breathing difficulties, and even death in extreme cases.
Even small quantities of the leaves can cause symptoms like nausea, vomiting, diarrhea, and burning in the mouth and throat. Ingesting larger amounts has led to more serious symptoms, including convulsions and coma.
The danger comes from mistaking the entire plant as edible. While the stalks are perfectly safe (and quite nutritious), the leaves should always be discarded. Cooking or boiling the leaves does not remove the toxins.
Gardeners who grow rhubarb at home should take special care to inform others about this risk, especially children or pets who might nibble on the leaves. Commercial rhubarb is usually trimmed properly, but homegrown rhubarb should always be handled with caution.
