Introduction: Continuous exposure of oxidants to the skin may disrupt the antioxidant balance and leads to inflammatory skin diseases (ISD). The aim of the present study was to compare the antioxidant activity, phenolic and flavonoid content of two traditionally used plants in ISD, Lawsonia inermis and Haplophyllum vermiculare. Methods: The hydroethanolic extract of the plants was prepared by maceration. Phenolic and flavonoid content of the extracts was measured respectively with Folin-Ciocateu and aluminum chloride methods. The monovalent reducing power and radical scavenging activity were also evaluated respectively by ferric reducing antioxidant power and 2,2-diphenyl-1-picryl-hydrazyl methods. Results: The reducing power of Lawsonia inermis (862.89±32.23 μmolFe2+/g) was significantly higher than Haplophyllum vermiculare extract (765.52±29.39 μmolFe2+/g). The radical scavenging activity of Lawsonia inermis extract at a concentration of 1000μg/ml (%65.72±0.77) was also significantly higher than Haplophyllum vermiculare (%36.34±2.52). The higher antioxidant activity of Lawsonia inermis is probably due to its higher phenolic (96.76±3.34μg GAE/mg) and flavonoid content (197.69±5.76μg QE/mg). Conclusion: Henna leaves had higher antioxidant activity, phenolic and flavonoid content compared to aerial parts of Haplophyllum vermiculare, and may be more effective in improving oxidative stress, prevention and treatment of ISD.