I've heard that nicotine (contained in tobacco) is even more toxic than potassium cyanide (KCN
, often used for suicide, at least in movies...).
I tried to research a bit, but could not find any directly comparable values and I'm not educated enough in toxicology to understand their meaning.
For nicotine, if taken in orally, I found values about 50-60mg/kg to be the lethal dose for adult humans. There were also sources mentioning far higher doses like 300mg/kg.
Finding lethal dose values for potassium cyanide was much harder, I found one source speaking of 200mg/kg orally for adults, but I'm not sure if that's true.
Can you please help me to compare the toxicity of those two substances and interpret them?