The present invention relates generally to chemical agents useful in the treatment and prophylaxis of inflammatory conditions or in the amelioration of symptoms resulting from or facilitated by an inflammatory condition in a mammalian animal including human and primate, non-mammalian animal and avian species. More particularly, the present invention provides a chemical agent of the macrocyclic diterpene family obtaining from a member of the Euphorbiaceae family of plants or botanical or horticultural relatives thereof or derivatives or chemical analogs or chemically synthetic forms of the agents for use in the treatment or prophylaxis of an inflammatory condition or in the amelioration of symptoms resulting from or facilitated by an inflammatory condition in a mammal, animal or avian species. The present invention further contemplates a method for the prophylaxis or treatment of mammalian, animal or avian subjects for inflammatory conditions including chronic or transitory inflammatory conditions or for ameliorating the symptoms of an inflammatory condition by the topical or systemic administration of a macrocyclic diterpene obtainable from a member of the Euphorbiaceae family or botanical or horticultural relatives thereof or a derivative, chemical analog or chemically synthetic form of the agent. The chemical agent of the present invention may be in the form of a purified compound, mixture of compounds, a precursor form of one or more of the compounds capable of chemical transformation into a therapeutically active agent or be in the form of a chemical fraction, sub-fraction or preparation or extract of the plant.