With intragastrical administration, baricitinib alleviated the development of skin and lung fibrosis in bleomycin-induced SSc-ILD mice based on the following observations: (i) alleviating dermal and alveolar septal thickening and alveolar structure destruction, (ii) inhibiting TGF-β1 signaling pathways in skin and lung tissue of SSc, (iii) suppressing fibroblast transformation and collagen accumulation in HFLs, (iv) TGF-β receptors influence the expression of JAK2 protein. This evidence concerns the gene JAK2 and pulmonary fibrosis.