This study was conducted to elucidate the effect of aqueous leaf extractof Nerium oleander and fruit extract of Melia azedarach on nucleic acidscontent and activity of some enzymes in Trichomonas vagina/is whichgrowth in Diamond's medium tryptone, yeast and maltose (TYM) media.Results indicated that the exposure of T. vagina/is to IC50concentration of N. oleander leaves and M azedarach fruits extractsshowed asignificant decrease in DNA content by 31.5% and 38.2%,respectively, while the RNA content decreased by 28.3% and 50.7%,respectively. Furthermore the totel.l. nucleic acids content decreased by27.9% and 48.1% , respectively, compared with the untreatedtrichomonads with plant extracts after 72 hours of growth.The results of this study also indicated that T. vagina/is treated withN. oleander leaves and M azedarach fruits extracts showed inhibed in theactivity of thymidine phosphorylase enzyme at rate 32.7% and 69.2%respectively compared with untreated trichomonads with plant extractsafter 72 hours of growth.From the results of this study, 1t is obvious that the above mentionedextracts possess an inhibitory effect on nucleic acids and on the activityof the enzyme Thymidine phosphorylase.