A pharmaceutical composition for obtaining an improved lung function in a human or an animal lung affected by airway obstruction such as COPD or asthma, is provided. The composition comprises a pharmacologically effective amount of activated carbon comprising adsorbed iodine and/or an adsorbed iodide salt and a sodium/iodide symporter inhibitor, such as perchlorate. Additionally, a method for obtaining an improved lung function in a human or animal lung affected by airway obstruction, such as COPD or asthma, is provided. The method comprises the steps of administering a pharmacologically effective amount of activated carbon comprising adsorbed iodine and/or an adsorbed iodide salt, and administering a sodium/iodide symporter inhibitor, such as perchlorate, in connection to the administration of the pharmacologically effective amount of activated carbon comprising adsorbed iodine and/or an adsorbed iodide salt.