digitalis

Drug that increases the efficiency of the heart by strengthening its muscle contractions and slowing its rate. It is derived from the leaves of the common European woodland plant Digitalis purpurea (foxglove).

It is purified to digoxin, digitoxin, and lanatoside C, which are effective in cardiac regulation but induce the side effects of nausea, vomiting, and pulse irregularities. Pioneered in the late 1700s by William Withering, an English physician and botanist, digitalis was the first cardiac drug.