Fibrosis is a pathological process that includes scar formation and overproduction of extracellular matrix by the connective tissue as a response to tissue damage. Pathologies include pathological scarring as colloid and hypertrophic scars in the skin, cirrhosis of liver and gallbladder, pulmonary and bone-marrow fibrosis, and scleroderma. The molecular process is not different from normal formation of connective tissue and extracellular matrix in the normal organs. Major profibrotic agents are type 2 CD4-positive lymphocytes, CD40 receptor and ligand interaction, and the cytokines interleukin-4, transforming growth factor-beta, and platelet-derived growth factor. The major antifibrotic agent is interferon-gamma. Fibrosis was considered an irreversible process, at least clinically, and is still usually treated by anti-inflammatory and immunosuppressive agents. No proven antifibrotic therapy has shown efficacy in ameliorating clinical fibrosis. Intravenous immunoglobulin has a very good safety profile, and was found to be an ameliorating agent for several fibrotic diseases, and hence could be a drug of choice to these patients and improve their quality of life.