This plant was originally used in Italy in eye drops to dilute the pupil in the eyes of women, producing a desired look at the time. The plant eventually stopped being used for this purpose as the toxicity of the plant lead to blindness. The plant can also be used in treating gastrointestinal issues, and some elements can be used to treat irritable bowel syndrome, even today.
The plant is administered in a powder, a tincture or as a decoction. The plant made an appearance in the movie The Nightmare Before Christmas, due to its association with witches and their spells.
Sally from The Nightmare Before Christmas with a jar of Deadly Nightshade (Source: The Nightmare Before Christmas by Tim Burton & Disney)