beta-Lapachone (LAPA) is a chemotherapeutic agent that can inhibit the expression of nitric oxide (NO) and inducible NO synthase (iNOS) in alveolar macrophages. No other information on the agent's anti-inflammatory activity has been reported. In the present study, we investigated the molecular mechanism of LAPA on lipopolysaccharide (LPS)-induced responses in BV2 microglia. Treatment of LAPA significantly inhibited NO and PGE(2) release in LPS-stimulated BV2 microglia. The inhibition of iNOS and COX-2 was also observed, suggesting the blockage of transcriptional levels. In addition, LAPA attenuated the expression of mRNA and proteins of proinflammatory cytokines, such as interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha in a dose-dependent manner. Moreover, LAPA exhibits anti-inflammatory properties by suppressing the NF-kappaB activation by blocking IkappaBalpha degradation and downregulating the ERK, p38 mitogen-activated protein kinase (MAPK) and Akt pathway. The results show that LAPA may be useful as a potential anti-inflammatory agent for attenuating inflammatory diseases.