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"Poisonous" does not mean deadly. Some manifestations of toxicity are subtle. The dose, as always, determines if a plant is safe source of nutrients or a toxic hazard.

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BRIEF: What are the most poisonous plants on earth?

I am contacting you on behalf of my 8th grade advisory class. The students are working on a research project. The project is trying to find out what are the most toxic or poisonous plants and animals on earth. The ending question they hope to answer is - What is the most poisonous living thing on earth? They have divided into several study/ research groups. One group is researching reptiles, another amphibian, still another spiders and of course plants. The plant group has concluded that the castor bean, rosary pea and( they think ) the hemlock rank as the top three. They have looked at many books and web sites. However, as an English teacher, I am not quite sure if I understand the fine points of some of the data base information. Can you help us?


I hope you do not leave out bacteria, dinoflagellates and other microbes. They are living things and make some potent toxins, and some of the toxins attributed to animals are actually made by microbes. I think they have it right about the most toxic plants. Rosary pea (Abrus precatorius), Castor Bean (Ricinus communis), and Water Hemlock (Cicuta genus, several species) would be my top three, also.