From selective interviews Thai folk doctors found that there were five Thai medicinal plants popularly used as antipyretic drug and to reduce fever in cancer patients. These are roots of Harrisonia perforata Merr (HP), Capparis micracantha DC (CM), Clerodendrum petasites S. Moore (CP), Ficus racemosa L. (FR) and Tiliacora triandra Diels (TT)[1]. The objective of this work wasto investigatetheir anti-microbial activities against S. aureus, B. subtilis, E. coli and C. albicans using the disc diffusion method [2]. Cytotoxic activity against lung (COR-L23) and breast (MCF-7)cancer cells and lung normal cells (MRC-5) was also tested by SRB assay [3,4]. The ethanolic extracts were tested for their activity. TT showed the highest inhibitory activity against S. aureus, B. subtilis, E. coli and C. albicans (clear zone=11.12, 13.8, 9.5 and 20.5mm respectively). HP and CP showed antibacterial activity against gram positive organisms only. TT and HP showed high cytotoxicity against MCF-7 (IC50=7.9 and 27.7µg/ml respectively) and CORL-23 (IC50=5.5 and 32.07µg/ml respectively). Surprisingly, there was no cytotoxic activity against lung normal cells or MRC-5 (IC50>50µg/ml). These results showed that TT should be investigated further to isolate active antimicrobial and cytotoxic compounds. These results support the use of these plants by Thai folk doctors as antipyretic drugs.