The current study was conducted in order to investigate promotional effects of herbal extracts on hair growth in an animal model of mice. There were four experimental groups, including distilled water (DW) as a negative control (NC), 3% minoxidil (MXD) as a positive control (PC), 50% ethanol (EtOH) as a vehicle control (VC), and herbal extract (HE) as the experimental treatment (E). The HE was extracted with ethanol from plants, including Gardenia, Mentha arvensis, Rosemary, and Lavender. Six-week-old C57BL/6 male mice were shaved with an electric clipper and the test materials were topically treated with 0.2 ml per mouse daily for three weeks. Photographic evaluation of hair re-growth was performed weekly during a period of three weeks. The number of mast cells was counted on the dorsal skin section of mice. The enzymes, alkaline phosphatase (ALP) and γ-glutamyl transpeptidase (γ-GT), were determined using a biochemical autoanalyzer. No clinical signs were observed in any of the experimental groups. As a result of photometric analysis, topical application of HE to dorsal skin for two weeks resulted in significantly faster acceleration of hair regrowth, compared with that of the NC or VC group (P<0.05). The PC and E groups showed a significant decrease in mast cell population, compared to the NC group. Activities of ALP and γ-GT were significantly increased in the PC and E groups, compared to the NC or VC group (P<0.05). Taken together, these results suggest that the herbal extract may have hair-growth promoting activity equal to that of MXD.