How do you think cyanide poisoning causes death?
Let's see how it works:
1) Poisoning caused by cyanide depends on the amount of cyanide a person is exposed to, the route of exposure, and the length of time that a person is exposed.
2) Breathing gas (cyanide) causes the most harm. Swallowing it can be toxic as well.
3) This cyanide gas is most dangerous in enclosed places.
4) This gas is less dense than air, so it will rise.
5) It prevents the cells of the body from using oxygen. After that, cells die.
6) It is more harmful to the heart and brain than to other organs. The brain and the heart use a lot of oxygen.
I would like to add this information to complete this question:
The liquid form of cyanide can be absorbed through the skin. Cyanide ions interfere with cellular respiration, resulting in the tissues of the body being unable to use oxygen.