ALDH1A inhibitor 673A is an ALDH1A inhibitor. ALDH1A inhibitor 673A inhibits all three ALDH1A family members ( IC 50 : 246 nM, 230 nM, 348 nM for ALDH1A1, ALDH1A2, ALDH1A3 respectively. ALDH1A inhibitor 673A induces necroptotic cell death preferentially in CD133+ ovarian CSCs. ALDH1A inhibitor 673A also inhibits chemotherapy-resistant tumor growth.