Belladonna is extremely poisonous and should not be used internally under any circumstances. It causes hallucinations and eventually death. Its a bushy plant that loves the shade, and is native all over Europe though it is also cultivated in North America. All parts of the plant are poisonous (leaves, roots, berries) and should not even be touched. It's considered a narcotic and a sedative, and the active compound is Atropine.
Latin: Atropa belladonna
Common names: Banewort, deadly nightshade, Devil's herb, divale, dwale, great morel, witch berries
Using in rituals
Belladonna is one of the ingredients in the infamous flying ointment of yore. If it was ever used, it wasn't on account of its gravity-defying qualities. The hallucinations were likely part of an astral travel ritual, which is what most scholars today feel was the real purpose of flying ointment. I don't recommend trying belladonna in any ointments.
In modern days, belladonna is not often used in rituals at all because of it's toxic nature. When it is, the purpose is usually astral travel but NOT ingested. Using it in a charm bag may be suitable, and if you were to burn it as incense, it should not be in an enclosed space.
The latin name (Atropa) comes from the name of the Greek Fate who cut the thread of life, due to its deadly potency.
It is also related to the Roman war Goddess Bellona. Warriors used belladonna in rituals before battle to invoke her battle frenzy. She was sometimes identified as the wife of Mars, but also sometimes as his sister. The herb is also sacred to Hecate.
Planet: Mars, Saturn
Element: Water
Deity: Bellona, Hecate