The invention relates to cell-free compositions obtained by culturing adult-derived human liver stem/progenitor cells (ADHLSC) in cell culture medium and isolating the resulting conditioned medium (ADHLSC-CM) that has advantageous property ties, such as anti-fibrotic effects. ADHLSC-CM, compositions based on ADHLSC-CM, and other related and derived products, can be used in cell culture processes or as a medicament, more particularly for the treatment of diseases involving organ injury, organ failure, in organ or cell transplantation or the pathological disruption, inflammation, degeneration, and/or proliferation of cells within a tissue or an organ, in particular within liver.