The purpose of this study was to investigate the effects of natural herb mixture containing Laminaria japonica Areschoung (LAM) on fine dust-induced bronchitis in mice. Laminaria japonica Areschoung is main content of LAM, which is including fucoidan. Fucoidan extracted from phaophyta is known to prevent bronchitis and to defend against bacteria and virus infection. In this study, we experienced the effect of LAM on bronchitis and investigated gene expressions (e.g ; IL-8, COX-2, MCP-1) and bio-markers (e.g ; IL-8, PGE2, MUC5AC) associated with bronchitis by using A549 cells. Also, we investigated whether LAM can suppress the bronchitis in fine dust-induced animal models. We injected fine dust (50 ㎕) twice as INT (Intra-Nasal-Trachea) method. Then LAM (200 mg/kg and 400 mg/kg) were oral administered for 14 days. We analyzed the number of immune cells, immunoglobulin E, bio-markers level associated with bronchitis. LAM significantly decreased bio-marker (IL-1β, IL-6, IL-8, TNF-α, Histamine, PGE2), immune cells (white blood cell, neutrophil, lymphocyte, monocyte), and immunoglobulin E, that are increased by fine dust. Taken together, this study suggest that LAM can be used as effective herbal extract for bronchitis.