Triclosan (TCS) is a chemical compound used in household products as biocide. However, their pulmonary toxicity has been unclear. Thus, the purpose of this study was to investigate the possibility of injury to the lung by inhalation of TCS. Rats were exposed to TCS by single intratracheal instillation of 10 µg/B.W. kg for the low-dose group and 1,000 µg/B.W. kg for the high-dose group, respectively. TCS induced increase in the level of total cell (TC) count, polymorphonuclear leukocytes (PMNs), total protein (TP), lactate acid dehydrogenase (LDH), tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in bronchoalveolar lavage fluid (BALF) at 1 day after instillation. However, most pulmonary toxicity marker levels except TP in BALF were restored 14 days after instillation. In addition, TCS led to reduction of cell viability with morphological change in lung eptiehelial cells (L2 cell). Therefore, TCS may affect responses of acute inflammation and permeability in the lung.