In a murine model of the steroid-resistant acute exacerbation of asthma, intraperitoneal NAC delivered 30 min before and 12 h after each ovalbumin (OVA) challenge reduced the airway hyperresponsiveness and decreased the neutrophil and eosinophil counts and inflammatory cytokines IL-13 and IL-5 in the BALF [139]. Here, IL5 is linked to airway hyperresponsiveness.