Piper tuberculatum, popularly known in Brazil as "jaborandi falso" and "pimenta darta", is widely used in folk medicine for the treatment of several diseases. In this study, the in vivo hollow fiber assay was used to investigate the antitumour efficacy of the crude extract and piplartine obtained from P. tuberculatum roots. Human glioblastoma (SF-295) and colon carcinoma (HCT-8) cell lines were used. In vitro cytotoxicity was assayed by the MTT assay. In the hollow fiber assay, nude mice implanted with tumour cells in hollow fibers were treated for four consecutive days via the intraperitoneal route, and tumour cell populations were assessed by the MTT assay. Both the crude extract and piplartine displayed cytotoxicity. In the hollow fiber assay, tumour growth inhibition rates were 24.6-54.8 % for the crude extract and 33.7-62.2 % for piplartine. No signal of toxicity was noticed. In conclusion, the crude extract and piplartine obtained from P. tuberculatum roots displayed in vitro and in vivo anticancer efficacy.