Bacterial infections and inflammation are among the ailments treated by traditional healers. The World Health Organization has expressed high interest in traditional medicine, and it is important to demonstrate scientifically that remedies employed in folk medicine are indeed therapeutically active. In this communication we report on antibacterial assays for 171 plant species, conducted under simple laboratory conditions in a private clinic in Trujillo, Peru. The aim of the study was to scientifically test if plants used in traditional medicine for the treatment of infections showed indeed antibacterial activity. Extracts of samples of 171 species were screened for antibacterial activity against Staphylococcus aureus and Escherichia coli, using agar-diffusion method. 14 species tested as traditional water extracts and 78 species extracted in ethanol showed activity against at least one of the bacteria. Simple laboratory conditions can be applied to validate the antibacterial properties of plants used in traditional medicine. While folk-medicinal uses can provide clear leads for scientific trails, many plants traditionally used against infections did not show any antibacterial activity, while plants used for different purposes yielded substantial activity. To make the most of these leads plant uses have to be very carefully documented however. What has to be taken into account is, that most traditional remedies are prepared as cocktails of different plants, where plant compounds possibly enhance and complement each other, and bioassays need to be extended to cover such compound preparations.