From a dichloromethane extract of Newbouldia laevis roots, four new (6-hydroxydehydroiso-alpha-lapachone, 7-hydroxydehydroiso-alpha-lapachone, 5,7-dihydroxydehydroiso-alpha-lapachone and 3-hydroxy-5-methoxydehydroiso-alpha-lapachone) and six known naphthoquinones have been isolated. Their structures