Potentilla L. (Rosaceae) species have been used in traditional medicine in Asia, Europe and Northern America. This study analyzed the biological activity of aqueous extracts of Potentilla species (Rosaceae): Dasiphora fruticosa (syn. P. fruticosa), P. norvegica, P. pensylvanica, P. thuringiaca, P. crantzii and P. nepalensis. The activities were tested using MTT, NR and DPPH assays on normal human colon epithelium (CCD 841 CoTr) and colon myofibroblast (CCD-18Co) cells. Moreover, cell morphology using the May-Grünwald-Giemsa method, IL-6 by ELISA, and nitric oxide (NO) analysis with the Griess method in culture supernatants were performed after 24 h. Extracts were tested at dose levels between 25 and 250 microg/mL. For ELISA, 15 microg/mL was chosen. All extracts suppressed the metabolism of myofibroblasts, while epithelial cells' mitochondrial dehydrogenase activity decreased after incubation with extracts. All extracts showed a free radical scavenging (DPPH) effect in a concentration-dependent manner. The most potent was the extract from D. fruticosa, while the least action was observed for P. thuringiaca. Potentilla extracts stimulated, IL-6 production in tested cells but the level of the cytokine was found to decrease in epithelial cells. Pre-incubation of cells with LPS resulted in increased IL-6 secretion. Modulation of NO production after extract addition and cell pre-incubation with LPS was also observed. Potentilla extracts may be interesting natural factors modulating the main features of cells forming the colon wall, and thus may be potentially useful in the prophylaxis or healing of colon disorders.