CpCDPK1/TgCDPK1-IN-3 (Compound 20) is a CpCDPK1 and TgCDPK1 inhibitor with IC 50 values of 0.003 and 0.0036 µM, respectively. CpCDPK1/TgCDPK1-IN-3 can be used in the research of apicomplexan protozoa-related diseases, such as the research of T. gondii , C. parvum and C. hominus infection.