A native to Europe, North Africa, and Western Asia, the herb grows wildly in many parts of the United States, mostly in dumps, quarries, near old ruins, under shade trees, or atop wooded hills. Belladonna is a branching plant that often grows to resemble a shrub of about 4 feet in height within a single growing season. Its leaves are long, extending 7 inches, and its bell-shaped flowers are purple with green tinges, about an inch long. The fruit and berries appear green when growing, but, as the toxins get stronger in the ripening stage, turn a shiny black color. Belladonna blooms in midsummer through early fall, and its roots are thick, fleshy, and white, growing to about 6 inches or more in length.

Deadly nightshade is one of the most toxic plants in the Eastern Hemisphere. While the roots are the most deadly part, the poisonous alkaloids run through the entirety of the plant. Scopolamine and hyoscyamine are among these toxins, both of which cause delirium and hallucinations. Deadly nightshade berries pose the greatest danger to children, as they are attractive and are deceptively sweet at first bite. Yet just two berries can kill a child who eats them, and it takes only 10 or 20 to kill an adult. Likewise, consuming even a single leaf can prove fatal to humans. Cattle, horses, rabbits, goats, and sheep can eat deadly nightshade without ill effect, though many pets are vulnerable to its lethal effects. 

Belladonna contains several tropane alkaloids, some of which are capable of blocking neurotransmitters in the central and peripheral nervous system. In this way it disrupts heart rate, breathing, sweating, and the involuntary movement of smooth muscles in the gastrointestinal tract. Someone suffering from belladonna poisoning can exhibit a loss of balance, sensitivity to light, slurred speech, hallucinations, and confusion. Due to the psychological effects, belladonna and related plants have been used as recreational drugs—a highly dangerous choice due to the exceptional risk of overdose and death. Still, others find it an effective anesthesia for surgery, as numbness and drowsiness are side effects of its toxic mix.

Symptoms of deadly nightshade poisoning present quickly, so if medical aid is far off, drink a large glass of warm vinegar or a mixture of mustard and water, which may dilute and neutralize its toxicity. 

A common pesticide and rat poison, strychnine has been targeted by animal rights groups who say the poison can cause violent, inhumane death. Very few would disagree with their assessment. Strychnine kills by blocking the function of an inhibitory neurotransmitter present in the spinal cord and brain that is usually responsible for quelling motor nerves. Without this off switch, motor neurons run out of control and the victim suffers spastic, painful muscle contractions. These convulsions can lead to hyperthermia, exhaustion, and oxygen depletion that eventually leads to asphyxiation.