A total of 58 extracts of different polarity were prepared from various organs of 16 species of Turkish plants and screened for their antitrypanosomal, antileishmanial and antiplasmodial activities. No significant activity was observed against Trypanosoma cruzi, whereas many extracts showed appreciable trypanocidal potential against T. brucei rhodesiense, with the CHCl3-soluble portion of Phlomis kurdica being the most active (IC50 2.7 mu g/mL). Almost all extracts, particularly the CHCl3, phases, exhibited growth inhibition activity against Leishmania donovani amastigotes. The CHCl3,-solubles of Putoria calabrica roots (IC50 1.9 mu g/mL), Wendlandia ligustroides leaves (IC50 2.1 mu g/mL) and Rhododendron lateum leaves (IC50 2.3 mu g/mL) displayed the highest leishmanicidal potential. The majority of the extracts also possessed antiplasmodial activity against the multi-drug resistant K1 Plasmodium falciparum strain. The most potent antiplasmodial activity was observed with the CHCl3, extracts of Phlomis kurdica (IC50 1.5 mu g/mL), P. leucophracta (IC50 1.6 mu g/mL), Scrophularia cryptophila (IC50 1.8 mu g/mL), Morina persica (IC50 1.9 mu g/mL) and the aqueous root extract of Asperula nitida subsp. subcapitellata (IC50 1.6 mu g/mL). Twenty-one extracts with significant antimalarial activity (IC50 < 5 mu g/mL) were also tested for their ability to inhibit the purified enoyl-ACP reductase (FabI), a crucial enzyme in the fatty acid biosynthesis of P. falciparum. The CHCl3, extract of Rhododendron ungernii leaves IC50 10 mu g/mL) and the H2O-soluble portion of Rhododendron smirnovii leaves IC50. 0.4 mu g/mL) strongly inhibited the Fabl enzyme. The preliminary data indicate that some (poly)phenolic compounds are responsible for the Fabl inhibition potential of these extracts. The presented work reports for the first time the antiprotozoal activity of nine different genera as well as a target specific antimalarial screening for the identification of P. falciparum FabI inhibitors from medicinal plant extracts. Copyright (c) 2005 John Wiley & Sons, Ltd.