This study document ed the information of significant ethnomedicinal plants fr om the traditional healers of three indigenous communities of Bangladesh. The documented data were quantitative ly analyzed for the first time in th is area. The benefits, importance and coverage of ethnomedicine w ere expressed through several quantitative indices including Informant Consensus Factor, Use Value , Frequency of Citation, Relative Frequency of Citation and Relative Importance Index. The agreement of homogeneity between the present and previous studies and among the indigenous communities was evaluated using Jaccard Index. A total of 159 ethnomedicinal plant species were documented from 174 informants. Importantly, 16 species were reported with new therapeutic uses and to our knowledge, 7 species described herein have never been ethnobotanically and pharmacologically studied. The present study showed that traditional treatments using medicinal plants is still widespread in the study area. Documentation of new ethnomedicinal species with their therapeutic uses shall promote further phytochemical and pharmacological investigations and possibly, lead to the development of new drugs. Further to the identification of suitable lead species, present study investigated the anti-cancer effects of the selected species using in-vitro and in-vivo studies. MTT assays on a panel of cancer cell lines have yielded promising p reliminary results. In parallel, fractionated extracts of the test species are undergoing testing for cytotoxic activity. These experiments represent the first formal investigation of the chosen species. These positive results corroborate the ethnomedicinal use of the selected plant and represent a starting point for subsequent investigations. Extracts which showed promising cytotoxicity will be investigated in more detail concerning (1) their activity towards cell lines from different types of solid cancers, (2) their active constituents by means of bioactivity-guided fractionation and isolation, and (3) their activity in in vitro and in vivo models .