Therapeutic and toxic effects of digitalis: William Withering, 1785

William Withering's classic description of the effects of digitalis was published in 1785. Although he was largely unaware of the drug's cardiac effects, he successfully treated many patients with congestive heart failure. He also recorded many striking examples of digitalis toxicity. This review highlights Withering's experience with "the foxglove," and summarizes modern concepts of digitalis efficacy and toxicity.