Collagen-induced arthritis in B6 mice is a valid model for testing anti-arthritic compounds. Arthritic B6 or DBA/1 mice were treated from the time of onset of arthritis with dexamethasone (Dex) (0.5 mg/kg per day), anti-tumour necrosis factor (TNF) monoclonal antibody (300 μg every 3 days), methotrexate (MTX) (0.75 mg/kg every 3 days), or indomethacin (Indo) (2.5 mg/kg daily) or the relevant vehicle. After 10 days of therapy, the clinical score was assessed and expressed as a percentage of vehicle-treated mice (n = 8 per group). Experiments were repeated twice. Data shown are from one representative study. *P < 0.05, **P < 0.01, ***P < 0.001. NS, not significant.