This study examined the effects of chondroitin sulfate (CS) alone and CS plus glucosamine sulfate (GS) in a dietary bar formulation on inflammatory parameters of adjuvant-induced arthritis and on the synthesis of interleukin-1beta (IL-1beta) and matrix metalloprotease-9 (MMP-9). Following 25 days pretreatment with dietary bars containing either CS alone, CS plus GS, or neither CS nor GS, rats were either sham injected or injected with Freund's complete adjuvant into the tail vein. Rats were fed their respective bars for another 17 days after inoculation. Parameters of disease examined included clinical score (combination of joint temperature, edema, hyperalgesia, and standing and walking limb function), incidence of disease, levels of IL-1beta in the serum and paw joints, levels of MMP-9 in the paw joints, paw joint histology, and joint cartilage thickness. Treatment with CS plus GS, but not CS alone, significantly reduced clinical scores, incidences of disease, joint temperatures, and joint and serum IL-1beta levels. Treatment with CS alone and CS plus GS inhibited the production of edema and prevented raised levels of joint MMP-9 associated with arthritis. Similarly, CS alone and CS plus GS treatment also prevented the development of cartilage damage associated with arthritis. Combination CS plus GS treatment in a dietary bar formulation ameliorates clinical, inflammatory, and histologic parameters of adjuvant-induced arthritis. The benefits of CS and GS in combination are more pronounced than those of CS alone. The reduction of arthritic disease by CS plus GS is associated with a reduction of IL-1beta and MMP-9 synthesis.