Today, the study of gut microbiota has taken a prominent place in several fields of medical research. Numerous experimental data in humans and animals suggest that an imbalance in the composition of the microbiota could contribute to the pathophysiology of systemic autoimmune diseases such as Systemic Sclerosis (SCS). A future exploration of the microbiota, a source of diagnostic and/or prognostic biomarkers, may be very useful for tomorrow's medicine by proposing therapeutic interventions based on the correction of possible imbalances in the intestinal flora. Studies of the human gut microbiota in patients with ScS are limited to low-impact investigations, due to the lack of data on the clinical and biological characterization of the patients studied, and to the absence of longitudinal studies in the same patient. For this reason, we are interested in exploring the intestinal microbiota of ScS patients in a comprehensive and longitudinal way.