The most poisonous substances often gathered based on their acute toxicity as measured by LD50: Lethal Dose.
LD50 is a mesure of the dose in a substance which kill half of a given population.
Here are presented the five most poisonous substances:
1. Botulinum toxins
Botulinum toxins are included in the family of neurotoxins and contains the most toxic substance known on human.
2. Snake venom
Most snake venom are a mixture of several proteins which are often neurotoxins. The speed of activity makes that some venoms might kill very quickly. This is a crucial information because a potent but slow-acting venom can leave enough to intervenes whereas a fast-acting poison with a lower LD50 can kill in some seconds.
Arsenic is a very toxic metals. This metal decouples the respiratory chain by substitution with phosphorus.
Polonium kills by emitting radiation which shreds sensitive biomolecule such as DNA and kills cells. The death is slow because of radiation poisoning.
Mercury is a type of metal poisoning. This is a heavy metal occurring in several forms. Less than one gram of this metal produce high toxicity or death. Mercury acts by blocking blood vessels.