Case in point--Digitalis purpurea, or Foxglove. Also known as:
- Bloody Fingers
- Dead Man's Bells
- Fairy Folk's Fingers
- Lamb's Tongue Leaves
- Lady's Gloves
It was first reported in medical literature by William Withering in 1785 as a treatment for irregular, fast heart rates (most likely atrial fibrillation) and dropsy, which was an English term for leg swelling that often accompanied congestive heart failure. Historically, it may have also been used to treat epilepsy, though this has since been proven to be ineffective.
Today, it's still used to treat both atrial fibrillation and congestive heart failure under the names digoxin, digitoxin, Crystodigin, and Lanoxin. It has not been proven to reduce mortality in these illnesses, and is currently being used less and less frequently.
Digoxin/digitoxin also has a very narrow therapeutic index. Too little of the drug and it doesn't help; too much causes serious toxicity. The window between these two thresholds is very tiny.
Toxicity can cause:
- loss of appetite
- nausea, vomiting and diarrhea
- jaundiced "yellow" vision
- blurry vision
- dangerous arrythmias, including slowed heart rate
- Vincent Van Gogh may have been treated with digoxin. Some theorize that his Yellow Period was due to digitalis toxicity, and the blurry stars of "Starry Night" might be evidence of toxicity as well. (photo credits)
- In 2003, Charles Cullen murdered 40 patients by administering fatal doses of digoxin while he cared for them as a nurse.
- The antidote to dig toxicity is called Digibind or DigiFab, which is an antibody that binds to digoxin.
- Reports of poisoning have occurred after children drank the water from a vase being used to display foxglove.
- The plant is toxic to cattle, dogs and cats.
- Poisoning has occurred in people brewing tea from foxglove leaves after they mistook them for innocuous comfrey leaves. Both plants have similar appearing furry leaves.
- Foxglove was one of the many herbs used in the prehistoric Clan of the Cave Bear books by Jean Auel.