ICAM-1-IN-1 shows significant efficacy in a rat rheumatoid arthritis model and in a mouse asthma model. ICAM-1-IN-1 reduces the width of inflamed ankles after the ninth day following treatment, but shows no efficacy in the acute phase. Treatment with ICAM-1-IN-1 (25 mg/kg) for 21 days significantly reduces the ankle inflammation of the arthritis rats. Significant reduction of eosinophils and serum-soluble ICAM-1 (sICAM-1) is observed.