Castor beans contain ricin, which is a lethal poison. It just takes an amount the size of a single grain of sand to kill someone. The toxin acts by inactivating ribosomes and stopping protein formation, which is deadly. The poison has no antidote, but it is possible to survive if the dosage is minimal enough. In 1978, Georgi Markov was assassinated with ricin. ¹⁾

Tetradotoxin or TTX is a potent neurotoxin that blocks sodium channels from shutting down the nerve passage between the brain and the body. A small dosage will induce weakness and lack of feeling, but just a little bit more paralyzes muscles that you use to survive. It takes about five hours for the full effect to take effect, but if the diaphragm ceases functioning, the lungs can no longer inhale or exhale, and the victim dies. Alternatively, an erratic pulse may cause the victim to die faster. ²⁾

The poison is found on the skin of poison dart frogs. The frogs themselves are not the toxin's origins — it comes from the food they eat. The poison is a neurotoxin that affects the functioning of the sodium channel. The result is paralysis and quick death. There is no antidote. ³⁾

Amatoxin is a deadly poison found in mushrooms. Even eating one mushroom can be enough to kill someone. It's a common mistake to misidentify mushrooms. Amatoxin attacks the liver and kidneys. The damage ultimately results in a coma and death. This isn't a quick death. ⁴⁾

Cyanide is a toxin that binds to iron in the blood, blocking oxygen from reaching the cells. A lethal dose can kill within minutes. This toxin is so widespread in nature that the body can detoxify small amounts. It's present in the seeds of apples, cherries, almonds, and apricots. ⁵⁾

Nerve gas does not need to be inhaled to be effective, as it is absorbed by the skin. Typically, survivors experience some kind of long-term neurological injury. VX may be much more potent, despite the fact that the nerve agent was never used in combat. VX activates an enzyme in the nervous system, causing it to fire signals incessantly. Death occurs from a lack of control of body functions, suffocation and convulsions. ⁶⁾

Brodifacoum is an effective anticoagulant that induces internal bleeding and death by lowering vitamin K levels in the blood. It kills rats because they eat the poisoned bait, but it also harms humans and pets because simply touching it will expose them. It penetrates the skin and lasts for months in the body. ⁷⁾

Strychnine is a natural poison that is mostly derived from the seeds of the Strychnos nux-vomica tree. It's a neurotoxin that acts on spinal nerves and causes patients to contort and convulse. It is used in poison for gophers and rats that are available on the market. It's unsafe to use, just like Brodifacoum, because it can harm infants, pets, and other accidental victims. ⁸⁾

Polonium is poisonous and the radioactivity causes the body's tissues to break down. This element's lethal dose is much lower than that of many of the other poisons listed previously. An adult can be killed by ingesting only 7 trillionths of a gram. ⁹⁾

White phosphorus is extremely poisonous to humans. The first stage of acute oral exposure to elevated levels of white phosphorus in humans is marked by gastrointestinal symptoms; the second stage is symptom-free; and the third stage is characterized by a rapid deterioration in condition with gastrointestinal effects, as well as serious effects on the kidneys, liver, cardiovascular system and central nervous system. Humans have experienced respiratory tract inflammation and coughing as a result of inhaling white phosphorus. Chronic exposure to white phosphorus in humans results in necrosis of the jaw, termed “phossy jaw.” ¹⁰⁾