Here, we review the biochemical and molecular properties of thymosin β₄ (Tβ₄), the major actin-sequestering molecule in eukaryotic cells, and its key role in dermal- and corneal-wound healing. Tβ₄ has several, novel, potential clinical applications in the repair and remodeling of ulcerated tissues and solid organs following hypoxic injuries, such as myocardial infarction and stroke. It might also have important repair functions in the pathophysiologic sequelae that are associated with actin toxicity and with septic shock, such as respiratory distress syndrome, multi-organ failure and severe tissue trauma.