Toxicity is usually measured in mouse units (MU), representing a dose of toxin that kills 50% of mice (LD50) when exposed to the toxic substance. In the following list ten of the most acute substances are ordered from least to most severe, a lethal dose for a 90kg individual is also shown. Although there are a lot more toxins and toxicants, these ten are well known and vary a lot in their respective lethal dose.
10 – Caffeine
Lethal dose: aprox. 18 grams
Though achieving lethal dose with caffeine would be exceptionally difficult with regular coffee unless you’re really trying to commit suicide, there have been reported deaths from overdosing on caffeine pills, with serious symptoms of overdose requiring hospitalization occurring from as little as 2 grams of caffeine. In cases of much larger overdoses, mania, disorientation and psychosis may occur; also rhabdomyolysis (breakdown of skeletal muscle tissue) can be provoked.
9 - Heroin
Lethal dose: aprox. 4 grams
Heroin, a semi-synthetic opioid drug synthesized from morphine, a derivative of the opium poppy. As with other opioids, heroin is used as both a pain-killer and a “recreational drug” and has an extremely high potential for abuse. Frequent and regular administration is associated with tolerance, moderate physical dependence, and severe psychological dependence. The name was derived from the German word “heroisch”, due to its perceived “heroic” effects upon a user. However, it was chiefly developed as a morphine substitute for the coughs that did not have its addictive side-effects.
8 - Dendrotoxin (black mamba venom)
Lethal dose: aprox. 1,5 grams
Dendrotoxins inhibit neurotransmissions by blocking the nerve impulses, in other words, paralyses the nerves. The victim of a black mamba byte soon experiences a tingling sensation in the mouth and limbs, dizziness, erratic heartbeat, double vision, severe confusion, fever, excessive perspiration, and lack of muscle control among other symptoms. If the victim does not receive medical attention, symptoms rapidly progress to severe abdominal pain, shortness of breath, shock, and paralysis. Eventually, the victim experiences convulsions, cardiac arrest, respiratory arrest, coma, and finally, death.
7 – Arsenic
Lethal dose: aprox. 2 g
Arsenic and many of its compounds are especially potent poisons. Arsenic disrupts intracellular energy transfer through several mechanisms, inhibits lipoic acid which leads to insufficient cellular and mitochondrial respiration. These metabolic interferences lead to death from multi-system organ failure, probably from necrotic cell death. Although arsenic causes toxicity, it can also play a protective role in leukemia treatment.
6 – Cyanide
Lethal dose: aprox. 1,3 grams
Most famous for spy movies and WWII documentaries; cyanide makes the cells of an organism unable to use oxygen, high concentrations of cyanide causes a coma with seizures, apnea and cardiac arrest, with inevitable death following in a matter of minutes. At the first stages of unconsciousness, breathing is often sufficient or even rapid, although the state of the victim progresses towards a deep coma, sometimes accompanied by pulmonary edema, and finally cardiac arrest. Skin color goes pink from cyanide-hemoglobin complexes.