(Rac)-Indoximod (1-Methyl-DL-tryptophan) is an indoleamine 2,3-dioxygenase (IDO) inhibitor. Co-treatment with IFN-γ and (Rac)-Indoximod markedly reduces the activity of human cardiac myofibroblasts (hCMs) expressing α-SMA and induces apoptosis through up-regulating the IRF-1, Fas, and FasL genes.