Abstract: Musk is the dried material secreted from the subnavel gland of male moskus. This drug was classified as a drug of superior quality in Shen Nung's Materia Medica (神农本草)and was recommended for the treatment of numerous diseases, especially for amelioration of pain and tissue swelling in traumatic and infectious diseases.In this study the anti-inflammatory effect of musk was evaluated on croton oil induced inflammation of the ear in the mice. The degree of ear swelling was significantly reduced (p<0.001) by the intraperitoneal or intravenous injection of the water soluble fraction of musk. The 50% inhibition dose (ID₅₀) for Musk-21, one of the active components isolated from the musk extract, was found to be 10mg/kg after iv injection. As the ID₅₀ for hydrocortisone was 30mg/kg in our animal model, the anti-inflammatory potency of Musk-21 was 3 times that of hydrocortisone on mg/kg basis.Further purification of Musk-21 yielded Musk-65, a product with anti-inflammatory potency at least twice that of Musk-21. Musk-51 was another active component which exhibited an anti-inflammatory effect no less than that of Musk-65.Studies on the chemical nature of these active components are in progress and will be reported separately.