and aims: Highly active oxygen causes DNA or protein damage. This study aimed to determine the effect of the extract of three medicinal plants, royal jelly, and metformin on the survival of human dermal fibroblast (HDF) cells under oxidative stress induced by H2 O2 . Methods: Hydroalcoholic extracts were prepared from Nigella sativa, Carum carvi seeds, and Taraxacum officinale flower. The growth curve of HDF cells was plotted in Dulbecco's modified eagle medium (DMEM). The cells were exposed to

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... H2 O2 stress and treated with different concentrations of the extracts, royal jelly, and metformin. The cells viability was then calorimetrically analyzed during different times in 69-well plates. Results: The exponential growth phase of HDF cells was observed during 24–72-hour growth. High cell survivals were seen during 72 hours of exposure to 25 mg/mL royal jelly (99.13±3.22%), 15 mg/mL C. carvi extracts and N. sativa (97.87±3.25% and 96.22±5.47%, respectively), 10 mg/mL royal jelly (96.14±4.72%), 16 mg/mL metformin (91.23±5.34%), and 8 mg/mL T. officinale (86.31±7.44%), respectively. These results were significantly higher than the results of 48 and 24 hours of exposure to 15 mg/mL N. sativa (P=0.013), 15 mg/mL C. carvi (P=0.019), and 16 mg/mL metformin (P=0.027). Moreover, royal jelly (25 mg/mL) significantly indicated greater effect on the cell survival compared with the highest concentrations of the extracts and metformin at different exposure times (P=0.016-0.032). Conclusion: Royal jelly, N. sativa, and T. officinale extracts revealed remarkable effects on the stressed HDF cells; therefore, they can be proposed for treatment of wounds and burns after clinical analysis.