An IL-6 production inhibitor which comprises a hydroxamic acid derivative of formula (I)
(wherein all the symbols have the same meanings as defined in the specification), an equivalent thereof, a non-toxic salt thereof or a prodrug thereof as an active ingredient. Because of having an IL-6 production inhibitory activity, the compound of formula (I) may be useful for the prevention and/or treatment of various inflammatory diseases, sepsis, multiple myeloma, plasma cell leukemia, osteoporosis, cachexia, psoriasis, nephritis, renal cell carcinoma, Kaposi's sarcoma, rheumatoid arthritis, hypergammaglobulinemia (gammophathy), Castleman's disease, intra-atrial myxoma, diabetes, autoimmune disease, hepatitis, colitis, graft-versus-host disease, infectious diseases, endometriosis and solid cancer.