Foxglove is the common name given to a genus of flowering plants, Digitalis. There are approximately 20 species, with the iconic purple Common Foxglove being the most recognized.
Both the common name, foxglove, and the scientific name Digitalis refer to the shape of the flowers. Digitalis means literally "fingerlike," and describes the flower quite well, as they can be fit easily over a small human finger. The name is a more whimsical play on this shape, as it is easy to imagine the flowers acting as mittens for some sort of small creature, such as a fox.
Many types of foxglove are poisonous, yet have a number of medicinal uses when taken in moderation. Their toxicity has lent them some darker nicknames, such as Witches’ Gloves and Dead Man’s Bells. Although the entire plant is poisonous, the upper leaves are by far the most toxic, and in extreme cases, ingesting even a small amount can result in death. In addition to potential fatality, it can also cause vivid hallucinations, delirium, severe abdominal cramping and pain, vomiting, diarrhea, nausea, and intense headaches.
If no treatment is taken, the symptoms of ingesting foxglove can continue to intensify. These may include serious nervous tremors, heavy visual hallucinations, a loss of cerebral function, a slowing of the pulse, and heart palpitations. Eventually these can lead to death.
Foxglove has been in use medicinally for a long time, and was first formalized as a cure in modern medicine in the late-18th century. It was primarily used at this time to treat certain heart conditions, acting as an antiarrythmic to treat people with irregularly fast heart rates. It continues to be prescribed to people who have atrial fibrillation.
The plant is also used by some people as a hallucinogen for both spiritual reasons and entertainment. Generally, however, the dangers of ingesting foxglove are high enough that it is recommended against recreationally. Like other poisons that cause hallucination, it can easily turn from inducing a trip to killing the user.
For similar reasons, foxglove has been largely abandoned, or at least had its prescription reduced, by the herbalist community. The applications of the plant are fairly limited, and are overlapped by many other, less dangerous, herbs. Since determining the proper dosage can be difficult, and the consequences can be extreme, only the most seasoned herbalists tend to prescribe it, and even then only if there is no other substitute.
Historically, the medical world used foxglove not only to control atrial fibrillation, but also to treat various seizure disorders, including epilepsy. As other treatments became more available, however, it was largely abandoned, and is now considered an ill-advised treatment by most medical professionals.