In ovalbumin (OVA)-sensitised BALB/c mice (a murine model of human asthma), PPAR-γ activation by ciglitazone treatment inhibited antigen-induced airway hyperresponsiveness (AHR), basement membrane thickness, collagen deposition and transforming growth factor (TGF)-β synthesis, lung inflammation, eosinophilia, cytokine production (IL-4, IL-5, IL-6 and IL-13), GATA-3 expression and serum levels of antigen-specific IgE and IgG1. The gene discussed is PPARG; the disease is airway hyperresponsiveness.