A new polyoxygenated briarane diterpenoid, briarenol B (1), was isolated from the octocoral Briareum excavatum and its structure determined from spectroscopic data. In RAW264.7 cells, a macrophage-like murine cell line, briarane B (1) was found to enhance the protein expression of pro-inflammatory cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS) in cells stimulated by lipopolysaccharide (LPS). </jats:p