Asthma is the most frequent chronic respiratory tract disease at children. The rate of its appearance in Poland is 8.6% among children. Its inflammatory basis is a cause that any even non-specific factor inducing inflammatory changes in respiratory tract can lead to asthma exacerbation. Children suspected of asthma or with already established diagnosis are frequent patients of pediatricians and family doctors. But once set diagnosis doesn’t exempt the doctor of vigilance and individual approach to every asthmatic patient. In the article we present a case of a patient with asthma exacerbation that was caused by foreign body set in bronchial tree. History of foreign body aspiration was initially negative. Despite of intensive treatment response to it was inadequate. In addition asymmetry of auscultatory pulmonary signs and characteristics of chest x-ray led to deepening and widening of the diagnosis. The foreign body was found in the bronchial tree and its removal allowed to gain control over asthma and to prevent further forced treatment and prawiits complication. Relapsing course of asthma and its chronic character make doctor lose his or her vigilance. Consecutive exacerbations are treated routinely especially if the response is satisfactory. On the other side, negative history of foreign body aspiration and its heterogeneous and non-specific course causes to misleading diagnoses. Furthermore antiasthmatic treatment can temporary mute the symptoms and suggests asthma the leading cause of the condition. Unrecognized foreign body leads to serious and irreversible repercussions, which are a consequence of leaving it in the organism as well as inappropriate harmful treatment of other overdiagnosed states.