The deadliest plant in the world is often considered to be the **Castor Oil Plant** (*Ricinus communis*). This plant contains a highly toxic substance called **ricin**, which can be deadly even in very small amounts. Ricin works by inhibiting protein synthesis in cells, leading to cell death. Ingesting even a small amount of ricin can cause severe abdominal pain, vomiting, diarrhea, and can be fatal within days if not treated promptly.
Other extremely poisonous plants include:
1. **Aconite** (*Aconitum napellus*), also known as wolfsbane or monkshood, which contains powerful neurotoxins that can cause heart failure.
2. **Oleander** (*Nerium oleander*), which contains cardiac glycosides that can cause heart arrhythmias and death.
3. **Poison Hemlock** (*Conium maculatum*), which contains alkaloids that cause respiratory collapse and death.
All of these plants are highly toxic, and ingestion or even contact with certain parts of these plants can be fatal.
source