FNDR-20123 is the first safe and effective anti-malarial HDAC inhibitor, acting on both Plasmodium falciparum HDAC (IC50: 31 nM) and human HDAC (IC50: 3 nM). FNDR-20123 inhibited HDAC1 (IC50: 25 nM), HDAC2 (IC50: 29 nM), HDAC3 (IC50: 2 nM), HDAC6 (IC50: 11 nM), HDAC8 (IC50: 282 nM) and, at nanomolar concentrations, HDAC3 (IC50: 2 nM). The inhibitor of HDAC subtype III was also observed at nanomolar concentrations.