[Wikipedia] Native Range, Invasiveness: Although Ricinus communis is indigenous to the southeastern Mediterranean Basin, Eastern Africa, and India, today it is widespread throughout tropical regions.[5] In areas with a suitable climate, castor establishes itself easily where it can become an invasive plant and can often be found on wasteland. (contributed by Mary Ann Machi)

[Wikipedia] Allergenicity and toxicity: Ricinus is extremely allergenic, and has an OPALS allergy scale rating of 10 out of 10. The plant is also a very strong trigger for asthma, and allergies to Ricinus are commonplace and severe.[20] The castor oil plant produces abundant amounts of very light pollen, which easily become airborne and can be inhaled into the lungs, triggering allergic reactions. The sap of the plant causes skin rashes. People who are allergic to the plant can also develop rashes from touching the leaves, flowers, or seeds. They can also have cross-allergic reactions to latex sap from the related Hevea brasiliensis plant. (contributed by Mary Ann Machi)