A study conducted to evaluate knowledge of and techniques for using prescribed inhalation devices among patients with asthma or COPD found that all of the asthma patients and 98.3% of the COPD patients claimed to know how to use inhaled medications. In the sample as a whole, 94.2% committed at least one error when using the inhalation device. Patients committed more errors when using metered-dose inhalers than when using the dry-powder inhalers. Although the majority of the patients claimed to know how to use inhalation devices, the fact that 94.2% committed at least one error shows that their technique was inappropriate and reveals a discrepancy between understanding and practice. Therefore, it is not sufficient to ask patients whether they know how to use inhalation devices. Practical measures should be taken in order to minimize errors and optimize treatment. Please click here to access the original English version of the full article as published in Jornal Brasileiro de Pneumologia.