Thymosin β4 (Tβ4) has been found to have several biological activities related to antiscarring and reduced fibrosis. For example, the anti-inflammatory properties of Tβ4 and its splice variant have been shown in the eye and skin. Moreover, Tβ4 treatment prevents profibrotic gene expression in cardiac and in hepatic cells in vitro and in vivo. In a recent study on scleroderma patients it was hypothesized that Tβ4 may exert a protective effect during human lung injury. In an ongoing study, we have explored the putative Tβ4 protective role in the lung context by utilizing a well-known in vivo model. We have observed significant protective effects of Tβ4 on bleomycin-induced lung damage, the main outcomes being the halting of the inflammatory process and a substantial reduction of histological evidence of lung injury.