1. Castor Plant
This deadliest plant is the most poisonous plant and yet it is very widely cultivated, castor plant on the whole is very toxic or poisonous you can say. The prominent part of the plant which is very poisonous is the seeds of the plant; castor plant actually contains ricin which is highly toxicities.
Ricin can also be found in the unprocessed castor oil but then it is purified, the symptoms of its poisoning includes diarrhea, pain in stomach and blood pressure etc. it can also leads the individuals to death and the main reasons which are caused due to this is severe dehydration along with hypotension, if it cannot be treated well the chances of the death becomes quite high.