Imiquimod-d 6 is the deuterium labeled Imiquimod. Imiquimod (R 837), an immune response modifier, is a selective toll like receptor 7 ( TLR7 ) agonist. Imiquimod exhibits antiviral and antitumor effects in vivo. Imiquimod can be used for the research of external genital, perianal warts, cancer and COVID-19.