Summary: Formoterol is an important drug in treatment of asthma and chronic obstructive pulmonary disease. Research in-dicates its high effectiveness, especially in combination with inhaled glucocorticosteroids. The side effects of this medicine ‒ mainly related to the cardiovascular system ‒ are minor. The available literature data provides ample evidence of formoterolʼs efficacy and safety in both asthma and COPD. Recent studies confirm the efficacy and safety of SMART therapy in asthma and show the benefits of using combinations containing formoterol in COPD patients, e.g. in terms of lower risk of tuberculosis.