this invention provides new therapeutic potential of nandrolone or a derivative thereof , against protozoal diseases . more specifically , nandrolone or a derivative thereof exhibits anti - protozoal activity against leishmania major . anti - protozoal potential of nandrolone derivatives , such as compounds 1 - 8 , can contribute in the development of effective therapies against protozoal diseases , such as leishmaniasis , trypanosomiasis , malaria , toxoplasmosis , babeosis , amoebic dysentery and lambliasis . another aspect of the invention is a method of testing derivatives of nandrolone for anti - protozoal activity comprising growing leishmania in the presence of the test derivative and determining the ic 50 value .