Patchouli alcohol (PA) is a chemical compound extracted from patchouli which belongs to the genus Pogostemon, herb of mint family. Recently, it has been reported that PA inhibits the production of inflammatory mediators. However, the biological mechanisms of PA for anti-inflammatory activities have not been studied. In this study, we investigated whether PA decreases the production of inflammatory mediators through downregulation of the NF-κB and ERK pathway. Our data indicated that PA inhibits the over-expression of iNOS and IL-6 in protein and mRNA levels in LPS-stimulated RAW264.7 and TNF-α stimulated HT-29 cells. PA inhibited IκB-α degradation and p65 nuclear translocation, and subsequently suppressed transcriptional activity of NF-κB in LPS-stimulated RAW264.7 and TNF-α-stimulated HT-29 cells. In addition, PA inhibited LPS- or TNF-α-stimulated ERK1/2 activation by decreasing phosphorylation of ERK1/2. These findings suggest that PA shows anti-inflammatory activities through suppressing ERK-mediated NF-κB pathway in mouse macrophage and human colorectal cancer cells.