Top 10 Most Deadliest Poisons In The World

7. Ricin

Ricin is a highly toxic, naturally occurring lectin produced in the seeds of the castor oil plant, Ricinus communis. A dose of purified ricin powder the size of a few grains of table salt can kill an adult human. The median lethal dose (LD₅₀) of ricin is around 22 micrograms per kilogram of body weight if the exposure is from injection or inhalation (1.78 milligram for an average adult). For comparison, a standard paracetamol (acetaminophen) tablet contains 500 mg of acetaminophen and a low dose aspirin contains 81 mg of aspirin. Oral exposure to ricin is far less toxic, and an estimated lethal dose in humans is approximately 1 milligram per kilogram.