A pharmaceutical composition is provided, where the pharmaceutical composition contains formula (I), (II), or (III) flavonoids which possess (PDE4), as a main ingredient. Especially, this composition has a binding affinity of high affinity rolipram binding sites (HARBS) of a PDE4 lower than a binding affinity of low affinity rolipram binding sites (LARBS) of the PDE4 is used in the treatment of asthma, chronic obstructive pulmonary disease (COPD), or chronic inflammation, and has bronchodilatory effects. In addition, whether the above-mentioned flavonoids have side effects, such as nausea, vomiting, gastric hypersecretion, etc., in accordance with their binding affinity to HARBS of particulates of brain cells are disclosed.