BackgroundChrysanthemum indicum, an oriental medicinal plant, has been shown to display a variety of pharmacological activities including antibacterial and anti-inflammatory effects. AimsIn this study, we evaluated the ability of C. indicum extracts to inhibit in vitro tyrosinase activity and the skin care effects of cosmetic formulations containing 0.5% C. indicum water extract in human volunteers. Patients/MethodsThe formation of dopachrome from (L)-dopa by mushroom tyrosinase was observed after treatments with C. indicum extracts. The volunteers received placebo (no extract) or test (0.5% C. indicum water extract) cosmetic cream and applied it on their face three times a day for 6 weeks. Biophysical skin parameters were measured every 2 weeks. ResultsChrysanthemum indicum methanol and water extracts dose dependently inhibited mushroom tyrosinase activity, and the effects of methanol extract were similar to those of kojic acid, a well-known tyrosinase inhibitor. Clinical evaluations revealed that application of cosmetic formulations containing C. indicum water extract time dependently reduced melanin levels over 6 weeks, whereas the placebo group showed no effect. No changes in moisture, elasticity, wrinkles, evenness, and pore size were observed in either group. HPLC-DAD-ESIMS analyses revealed that luteolin and acacetin-7-O-rutinoside are the major flavonoid compounds in C. indicum water extract. ConclusionThese results suggest that C. indicum water extract could be applied as a natural skin-whitening agent for functional cosmetic uses, due to its melanin-reducing efficacy.