Poisonous nightshade, also known as deadly nightshade or Atropa belladonna, is a perennial herbaceous plant native to Europe, North Africa, and Western Asia. It features bell-shaped purple flowers and shiny black berries. All parts of the plant contain toxic alkaloids, making it highly poisonous if ingested. Historically, belladonna has been used in traditional medicine, but its toxicity poses significant risks. Symptoms of poisoning can include dilated pupils, sensitivity to light, blurred vision, tachycardia, and hallucinations. Due to its dangerous nature, caution is advised when encountering this plant in the wild.