Clinacanthus nutans (C. nutans) leaf extracts have been widely used by cancer patients in Malaysia and local practiceclaims a cure to cancer. There were several studies done to determine the cytotoxicity potency of C. nutans extracts onvarious types of cells. However, there is still lacking on the knowledge regarding the combination effect of C. nutanswith anticancer drugs. Thus, the study was carried out to determine the cytotoxicity potency of C. nutans extracts andpaclitaxel (PTX) alone and, in combination on MDA-MB-231 cells. The cells were treated with 100% ethanol extract ofC. nutans (CNE) and water extract of C. nutans (CNA), PTX and combination of both extracts and PTX for 72 hours andthe cytotoxic activity was determined using SRB assay. Result showed that CNE had little cytotoxic activity, whereas CNAshowed no cytotoxic activity on MDA-MB-231 cells. For combination treatment of C. nutans extracts and PTX, only CNEshowed significant enhanced PTX-induced cytotoxicity (p < 0.05), meanwhile CNA inhibited PTX-induced cytotoxicitysignificantly (p < 0.05). As a conclusion, CNE was able to increase PTX potency to inhibit the viability of MDA-MB-231cells.