A model to illustrate how CsA treatment can modulate outcome of the healing process. CsA contributes to extracellular matrix accumulation through reduction of MMPs expression (MMP/TIMP balance) and modulation of collagen accumulation. In non-healing wounds reducing MMPs expression by CsA treatment promotes a healing process that resembles scarless healing. Scarless healing (e.g. gingival tissue and nude skin) is characterized by a modest elevation of the MMP/TIMP ratio which is shifted by CsA treatment to a balanced MMP/TIMP ratio (1:1) and results in healing with scar formation. Further suppression of the MMP/TIMP and increasing collagen content progresses from regular wound healing with scar formation to the overgrowth of scar tissues.