Clinacanthus nutans (C. nutans), a well-known ethnopharmacological plant consumed for its medicinal purposes by Southeast Asian communities. C. nutans is said to possess antipyretic, inflammatory, antiedemic as well as analgesic properties and used traditionally in treating various skin ailments, Herpes infection, cancer and diabetes. The young leaves of this C. nutans are consumed in Malaysia for maintaining health. In this study, the proliferative activity of human gingival fibroblast cells (HGF-1, ATCC®CRL-2014™, USA) treated with the ethanol extract obtained from C. nutans leaves at three different concentrations (250, 125 and 62.5 µg/ml) was compared with the untreated cells using alamarBlue assay. The proliferative activity of HGF-1 using alamarBlue assay showed that the cells treated with 62.5 μg/ml of ethanolic extract of C. nutans leaves exhibited increased proliferation compared to the other groups and hence does not exhibit any cytotoxicity on HGF-1.