How do scientists actually calculate the lethality of poisons?

Question

For example, I read that 5g of cyanide is enough to kill 35 people. What does that even mean? If I could somehow split 5g of solid cyanide (is that a thing?) into 35 parts and put it in 35 peoples’ Dr. Pepper they would all die? And how could you possibly test that?

In: 62

Answer 1

Regrettably it’s discovered by animal testing. Brakes have been used for a long time. The scientists attach masks to the dogs and pump the mask full of poison at increasing concentrations until half of the dogs die. That then gets extrapolated to become the LD50. Don’t Google it, it’s heart breaking to see what they do to these dogs.