Whole root preparations of three Nigerian medicinal plants, Anthocleista djalonensis, Nauclea latifolia and Uvaria afzalii, used traditionally in combination treatment of sexually transmitted diseases (STD), were extracted by maceration in ethanol, cold and hot water, respectively. The extracts were tested, by agar diffusion and macrobroth dilution methods, for activity against five strains of Staphylococcus aureus and two of Escherichia coli isolated from cases of STD and or urethritis. Four typed bacterial strains, S aureus ATCC 12600, Bacillus subtilis ATCC 6051, Pseudomonas aeruginosa ATCC 10145 and Escherichia coli ATCC 117755 were included as reference organisms. Ethanolic and cold-water extracts of Anthocliesta djalonensis exhibited activity against 9 and 7, respectively, of the 11 test organisms. They were bacteriostatic at minimum inhibitory concentrations (MIC) to the Gram positive strains but bactericidal to the Gram negative strains. Similar crude extracts of Uvaria afzalii showed bactericidal activity restricted to Gram positive (Staphylococcus aureus and Bacillus subtilis) strains. Nauclea latifolia extracts were bacteriostatic to both Gram positive and Gram negative strains. No test strain was susceptible to the hot water extracts of Nauclea latifolia but five and seven strains, were respectively susceptible to similar extracts of Anthocliesta djalonensis and Uvaria afzalii. Of the seven column chromatographic fractions of the ethanolic extract of Uvaria afzalii, F(ua-1) exhibited a bactericidal activity restricted to the Gram negative Escherichia coli strains, which were not susceptible to the crude extract. Fractions, F(ua-2), F(ua-3) and F(ua-4), like the crude extract, were bactericidal against the Gram positive strains only. Thus, partial purification seems to broaden the spectrum of activity and generally improve the potency of Uvaria afzalii. These results apparently justify the use of the three plants in treatment of STD.