The anti-Helicobacter pylori effect of the extracts and fractions obtained from seven Turkish plants, which are used in folk medicine for the treatment of gastric ailments including peptic ulcers, were studied against one standard strain and eight clinical isolates of H. pylori by using the agar dilution method. Flowers of Cistus laurifolius and Spartium junceum, cones of Cedrus libani, herbs and flowers of Centaurea solstitialis sap. solstitialis, fruits of Momordica charantia, herbaceous parts of Sambucus ebulus, and flowering herbs of Hypericum perforatum were evaluated in this study, Results showed that all except one extract from six of these plants showed activity against the microorganism with MICs between 1.95 and 250 mu g/ml, with S. junceum being the only inactive species. Amongst the active plants the inhibitory properties of C. laurifolius were found prominent. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.