William Withering

William Withering was an English botanist, geologist, chemist, physician and first systematic investigator of the bioactivity of digitalis. He carried out what many regard as the first real clinical trial. 

He attended Edinburgh Medical School from 1762 to 1766 after which he started work as a consultant at Stafford Royal Infirmary.

William's interest in plants was sparked by his wife, Helana, who was a botanist. He is credited with carrying out one of the first real clinical trials, where he tested various extracts of digitalis on over 100 patients to determine the most effective way of administering the extract. His findings were published in his 1785 paper, "An account of the foxglove and some of its medical uses". 

Through his work, William identified the essential ingredient in a herbalist's prescription, digitalis purpurea, and demonstrated its value in treating patients with cardiac failure. He also identified the symptoms of digitalis intoxication and established rules for prescribing.