Abstract: It has now been discovered that inhibitors of soluble epoxide hydrolase (“sEH”) are useful in reducing the severity of or inhibiting the progression of obstructive pulmonary diseases, restrictive airway diseases, and asthma. Administering a cis-epoxyeicosantrienoic acid (“EET”) in addition to the inhibitor is at least additive, and may be synergistic, in reducing or inhibiting these conditions and diseases, as measured by reduced numbers of neutrophils present in the lung. The inhibitor of sEH may be a nucleic acid, such as a small interfering RNA.