Medical consultations by letter are especially abundant in the 18th century; recent research in the history of medicine has focused on this kind of archives, hoping to get a better idea of lay medical culture and medical practice, everyday life of the patient in the early modern period, private experience of suffering, relationships between popular knowledge and medical theories of illness, as well as the major factors of the doctor-patient relationship. However, to interpret them is not an easy nor an univocal task. This article suggests to analyse medical consultations by letter as an elaborate practice, starting from the communicational structure of the material in order to legitimate a two-scale approach, i.e. from the perspective of the healer and the person who is asking for a healing advice. In the first case, we analyse the correspondence of the Bernese physician Albrecht von Haller (1708--1777), and in the second case, the correspondence of the Vaudois physician Samuel-Auguste Tissot (1728--1797), with the aim of developing an approach of systematic comparative research