A petroleum ether extract of Peperomia galoides showed significant in vitro activity against three Leishmania species and Trypanosoma cruzi. Three major prenylated diphenols, including two known compounds, grifolic acid [1], and grifolin [2], and the new substance piperogalin [3], have been isolated. Structures were established on the basis of spectral analysis including 2D nmr spectroscopy.