After leaving Edinburgh, Withering's first appointment was as Physician at Stafford General Infirmary where he met his future wife Helena Cookes, to whom he was married in 1772. Withering left Stafford three years later to take up a post at Birmingham General Hospital and it was while travelling back to the town to see patients at the Infirmary that he chanced upon his greatest medical discovery. During the course of the journey, as the horses pulling his coach were changed, Withering was asked to consult an elderly woman suffering from Dropsy (a general swelling of the body caused by an accumulation of fluid, known nowadays as congestive heart failure) whom he diagnosed as having little chance of recovery. Passing by several weeks later, Withering enquired of the woman's health and was surprised to be told she had in fact recovered, thanks to a recipe supplied by a 'Grand Old Dame' from Shropshire! After experimenting with the 20 or so herbs contained in the mixture, Withering concluded that the active ingredient that had cured the patient was contained in the leaves of the purple foxglove (Digitalis Purpurea).