Aqueous and alcoholic extracts are obtained from the roots, leaves and stems of ruddy mangrove-tree (Rhizophora mangle L.), a very common plant in Cuban coasts and to which different curative properties are attributed in our popular medicine. The inhibitory activity of these extracts on the growth of different human pathogenic organisms, among which are bacteria, fungii and yeasts, is reported. For this determination, a method of diffusion in an agar medium with holes in which 50 ml of each extract in question were poured was used; the size in millimeters of the inhibitory halo found in each species and the concentration of the dilution in broth for Mycobacterium strains are reported.