The invention relates to use of a diterpene from a coral, excavatolide B, or an analogue thereof for treating a disease associated with inducible nitric oxide synthase, cyclooxygenase-2 and/or matrix metalloproteinase. The invention also relates to use of a diterpene from a coral, excavatolide B, and an analogue thereof for treating a disease associated with TNF-α and/or IL-6 over-expression.