Digitalis lanata (often called woolly foxglove or Grecian foxglove) is a species of foxglove. It gets its name due to the texture of the leaves. Digitalis lanata, like some other foxglove species, is toxic in all parts of the plant. Symptoms of digitalis poisoning include nausea, vomiting, severe headache, dilated pupils, problems with eyesight, and convulsions at the worst level of toxicity. The plant is also harmful to other animals. In some cases it is considered invasive or a noxious weed. Minnesota is one of the few places that consider it invasive as noted by the Western Weed Society. It is in leaf all year, in flower in June and July, and the seeds ripen in early-mid September. The flowers are hermaphroditic (having both male and female organs). Bees pollinate the flowers.
Digitalis lanata contains a powerful cardiac glycoside that may be used by patients with heart conditions. Digoxin (digitalin) is a drug that is extracted from Digitalis lanata. It is used to treat some heart conditions such as atrial fibrillation. It slows atrioventricular conduction so that the heartbeat slows down and slightly increases contraction power (positive inotropic effect). Because of the improved circulation in congestive heart failure caused by fast atrial fibrillation, the kidneys can function better, which stimulates the flow of urine, which lowers the volume of the blood and lessens the load on the heart. This is the effect that was first described when the plant was discovered as a medicine (Withering 1785). Digitalin was not discovered until the mid-19th century by two French scientists Homolle Ouevenne and Theodore Ouevenne. It was not until 1875 that Oscar Schmiedberg identified digoxin in the plant. It was first isolated in the 1930s in Britain by Sydney Smith. At that time it was used to treat ulcers in the lower abdomen, boils, headaches, abscesses, and paralysis, and externally healing wounds. Today it is still extracted from the plant because synthetis is quite expensive and difficult. However, it is becoming less frequently used due to the narrow therapeutic margin and high potential for severe side effects. Digoxin is being replaced by newer drugs including beta blockers, angiotensin-converting enzyme inhibitors, and the calcium channel blocking agents. As new pharmacotherapeutic agents arise, the use of digitalis preparations is expected to continue to decline. There are also other commercial uses for Digitalis lanata other than heart conditions. For example, in South America the powdered leaves are used to relieve asthma, as sedatives, and as diuretics. In India it is included in an ointment that contains digitalis glycosides used to treat wounds and burns.