Lapachol, a natural naphthoquinone, is an orally active, potent DHODH inhibitor. Lapachol has immunosuppressive activity on lymphocytes through its direct ability to block DHODH activity and inhibit pyrimidine synthesis. Lapachol is a vitamin K antagonist with antitumor activity and can inhibit DNA and RNA synthesis in neoplastic cells. Lapachol has anti-Leishmania activity[1][2][3].