Hexamethylene bisacetamide is a tumor cell-differentiating agent. It induces complete differentiation of 754A murine erythroleukemia cells when used at a concentration of 5 mM. Hexamethylene bisacetamide also induces latent HIV-1 viral production in chronically HIV-1-infected U1 cells in a concentration-dependent manner. Implantation of HT-29 colon cancer cells cultured with hexamethylene bisacetamide for seven, but not 28, days reduces tumorigenesis of those cells in mice.