Deadly nightshade
Deadly nightshade (Atropa belladonna), also known as belladonna or dwale, is a well-known perennial herbaceous plant, with leaves and berries that are highly toxic and hallucinogenic.  It is in the nightshade family (Solanaceae), which it shares with potatoes, tomatoes, eggplants, jimsonweed, tobacco, and chili peppers. In addition, Solanum nigrum is also called Deadly nightshade.
The Belladonna is native to Europe, North Africa, and Western Asia, and has become naturalized in parts of North America. It is not nearly as common in the wild as many field guides would suggest. This is because it is readily attacked by mint flea beetles Longitarsus waterhousei and has a low tolerance for direct sunlight. In areas where it has become naturalized it can often be found in shady, moist areas with a limestone-rich soil.

# Description
The Belladonna has dull green leaves and bell-shaped flowers that are an unremarkable shade of purple, which yield black, shiny berries measuring approximately 1 cm in diameter. The yellow form (Atropa belladonna var. lutea) has pale yellow flowers and fruit. The berries are sweet, but most of their alkaloids are in the seed.  It is an herbaceous plant, and can grow to be approximately five metre tall. The leaves have an oily, "poison ivy"-like feel and can cause vesicular pustular eruptions if handled carelessly.  Many animals, such as rabbits, birds and deer, seem to eat the plant without suffering harmful effects, though dogs and cats are affected. Many reports suggest that people have been poisoned by eating animals which have previously eaten Belladonna, though this has not been verified and many sources point that there are no poison substances in the berries. Recent experiments with humans have proven this myth of poison incorrect, though pets may still be affected. The taste of the berry is said to have initially been a deterrant, though it is said to become an 'acquired taste' after a while.
When Belladonna is in its first stages of growing the star shaped base of the berries is barely visible.
Germination is often difficult due to the presence of germination inhibitors in the seeds. Belladonna is not common as a garden plant, and is considered a weed in some areas. Belladonna is a perennial branching herb growing to 5 metre tall, with 18 cm long ovate leaves. Belladonna contain the heaviest leaf in its angiosperm group. It is not a very hardy perennial and is sensitive to being transplanted.  Germination requires several weeks in warm, moist, absolutely sterile soil, usually far from normal garden conditions.

# Toxicity
Belladonna is one of the most toxic plants found in the Western hemisphere.  Children have been poisoned by eating as few as three  berries. Ingestion of a leaf of the Belladonna can be fatal to an adult. The root of the plant is generally the most toxic part, though this can vary from one specimen to another. See Harrison's Principle's of Internal Medicine. (11th edition, page 842: "Antimuscarinic Compounds: fatalities have occurred from as little as 10 mg atropine, but doses of 500 mg have been non-fatal.Young children are particularly susceptible to poisoning with belladonna alkaloids.")
All parts of the plant contain tropane alkaloids.  The berries  pose the greatest danger to children because they look attractive and have a somewhat sweet taste. Symptoms of belladonna poisoning are the same as those for atropine (a tropane alkaloid), and include dilated pupils, tachycardia, hallucinations, blurred vision, loss of balance, a feeling of flight, staggering, a sense of suffocation, paleness followed by a red rash, flushing, husky voice, extremely dry throat, constipation, urinary retention, and confusion.  The skin can completely dry out and slough off.  Fatal cases have a rapid pulse that turns feeble. The antidote is physostigmine or pilocarpine, the same as for atropine.
The reason for most of these symptoms is atropine's effect on the parasympathetic nervous system. Atropine competitively inhibits the action of acetylcholine (ACh) at the acetylcholine receptor in the nerve synapse, thereby preventing the parasympathetic nervous system from sending out electrical nerve impulses. Since the parasympathetic nervous system regulates non-volitional/subconscious activities (such as sweating, breathing, and heart rate) when it is prevented from sending out signals, the heartbeat and breathing become extremely irregular.
The Belladonna is toxic to many domestic animals and livestock; Belladonna poisoning can lead to colic, depression, weakness, and lack of coordination in horses, with fatalities reported even for small amounts from 1 to 10 pounds (0.5 to 5 kg).

# Uses

## Cosmetics
The name belladonna originates from the historic use by women (Bella Donna is Italian for beautiful lady) to dilate their pupils; an extract of belladonna was used as eye drops as part of their makeup preparations. The Belladonna toxin's atropine content had the effect of dilating the pupil, thus making their eyes supposedly more attractive.  It is now known that atropine has anticholinergic activity - by blocking the ability of the iris to constrict, mydriasis results.  Dilated pupils are considered more attractive because pupils normally dilate when a person is aroused, thus making eye contact much more intense than it already is. It had the adverse effect of making their vision a little blurry and making their heart rates increase. Prolonged usage was reputed to cause blindness.

## Modern medicine
The plant is an important source of atropine, which is an effective treatment for the effects of poisoning by cholinesterase inhibitors such as Parathion and Malathion. Atropine will also reverse the effects of poisoning by nerve agents designed for chemical warfare. In Europe, the plant is specifically cultivated for this purpose. While atropine can treat the symptoms of poisoning from these organophosphate compounds, the antidote is the unrelated compound pralidoxime.
Optometrists and ophthalmologists use atropine for pupil dilation in eye examinations, though the dose used is  small.  Atropine degrades slowly, typically wearing off in 2 to 3 days, so tropicamide and phenylephrine is generally preferred as a mydriatic.  Atropine is contraindicated in patients predisposed to narrow angle glaucoma.
Belladonna (as Atropa Belladonna Extract) can also be found in some over-the-counter cold and flu medicines (in small amounts) due to its pseudoephedrine-like qualities of clearing up nasal and other passages where mucus forms.
Being parasympathomimetic, Belladonna (by prescription as a syrup) is also used to treat colicky babies, as the gut naturally produces atropine, and it is thought that colic develops due to inadequate atropine production.  The Gastrointestinal tract is one of the last systems to form before birth, so it is thought that the inadequate atropine production is a result of the GI tract not being finished developing at birth, thus resulting in colic. Belladonna supplements the gut until there is adequate atropine production.

## Alternative Medicine
Homeopathy uses Belladonna to treat a variety of afflictions, including sore throat, and conjunctivitis.

## Recreational drug
Occasionally, the plant is used for recreational purposes:  it is consumed in the form of either a tea or simply raw, which can produce vivid hallucinations, described by many as a 'living dream'. Upon consumption of this plant, the user will experience all the severe, adverse anticholinergic effects before hallucinating and continue to do so while hallucinating. Use for recreational purposes is considered dangerous because of the risk of accidental overdose.
It has been suggested by Alexander Kuklin's book How Do Witches Fly? that the aconitine in aconite (another toxic hallucinogen) can counter/reduce the toxic effects of atropine in belladonna, while combining their hallucinogenic effects, and that this combination of belladonna and aconite was used by witches in the Middle Ages.

## Folklore
Stories claim that the devil has the exclusive rights to plant and harvest this plant. Hence, anyone eating it is visited and killed by the devil. Many also believed it was a temptation for greedy children as the berries seem to be offered on green, pentagram plates and look very appetizing.
Belladonna is sometimes claimed as a cure for lycanthropy.

# Trivia
- Alcoholics Anonymous co-founder Bill Wilson reports having undergone the "belladonna cure" while hospitalized for what would become his final encounter with alcohol in 1935.
- The 1998 fantasy movie "Practical Magic" had Sandra Bullock's character mixing it in a bottle of tequila to sedate the abusive boyfriend of Nicole Kidman's character, but an overdose kills him instead.
- The fictional character Sally in Tim Burton's The Nightmare Before Christmas uses Deadly Nightshade several times in the movie to get away from her master Doctor Finklestein
- Belladonna features prominently in the 2007 movie Perfect Stranger starring Halle Berry and Bruce Willis.  The character played by Nicki Aycox is killed by belladonna ingestion and is found to have had her pupils dilated with the substance.