The word "Cyanide" is derived from the Greek "kyanos", meaning dark blue. It was first obtained by the heating of the pigment known as Prussian blue (Fe₄[Fe(CN)₆]₃)
While not every Cyanide compound is dangerous, Sodium cyanide (NaCN), potassium cyanide (KCN), hydrogen cyanide (HCN), and cyanogen chloride (CNCl) are lethal in small doses.
It doesn't take much Cyanide to kill a human. The lethality of a substance is often measured in the LD50 scale. This is the amount of substance needed to kill 50% of a population (Lethal Dose 50). This is often used in combination with body mass to determine relative concentrations (a small person will need less poison to die than a large person).
The LD50 of water, as an example, is 90g/kg. This means a 75kg person (~165lbs) would need to consume 6750g of water to hit this concentration. While our kidney can process about 1000g of water an hour, a woman died drinking 6 liters of water and holding her pee for a contest.
The LD50 for Sodium Cyanide in rats is about 4.3mg/kg, while the LDLo (Lowest Lethal Dose) recorded in humans was 1.3 mg/kg. That means a 98mg dose (less than 1/10 of a gram) would be enough to kill.
Even water and caffeine can be deadly in high volumes, but Cyanide packs a more potent punch
The Mechanism of Action of CN-; irreversible binding of the heme ring in Cytochrome C
Doctors need to understand how a chemical interrupts the normal function of our physiology to begin to fix it. In the case of CN-, the ion binds to an important protein found in Cytochrome. The heme ring (seen in the figure) usually binds to O2, which is an important step of ATP transport within the mitochondria of our our cells. Without this normal function, our cells can not produce ATP and will die rapidly.
Cyanide has strict access restrictions and is typically only available to those with government authorized research credentials. If you know a smart woman with academic access to Cyanide, don't make her angry!
0.6 mg of hydrogen cyanide per gram: 83–500 apple seeds to develop acute cyanide poisoning
0.01–1.1 mg of amygdalin (breaks down to HCN in the body): 60 pits of red or black cherries may lead to cyanide toxicity
According to scientific analyses, 4-5 raw apricot seeds contains about 45mg of hydrogen cyanide
Bitter almonds have 40x the cyanide concentration of sweet almonds. 10oz of bitter almonds can provoke cyanide toxicity.
LDLo for Hydrogen Cyanide (Lowest Lethal Dose) recorded in humans was 0.54 mg/kg. It could take as little as 40mg of Cyanide to kill a 150 lb person. While some articles will suggest that amygdalin isn't that dangerous, and advocate for its use in some Chinese medicine, are you willing to take the chance?
3-1-0: Flammability risk, mild health risk