The lung represents a particularly useful target for this research as (a) many lung diseases involve acute or chronic inflammation or cell proliferation, which are processes targeted by PPARγ ligands, (b) drugs can be delivered by inhalation, possibly sparing systemic side effects like heart disease and weight gain, and (c) PPARγ ligands appear particularly effective against lung fibrosis, a disease for which effective therapy can be challenging. This evidence concerns the gene PPARG and pulmonary fibrosis.