Summary: One consequence of the increased use of antibiotics in recent years is the increased frequency of observed adverse reactions. Individual patient reactions to antibiotics can vary widely, but the predominant trend is toward non-life-threatening delayed-type hypersensitivity reactions, particularly skin rashes. Beta-lactam antibiotics are the most common cause of hypersensitivity reactions – other groups are responsible for less than 3% of such reactions. The lack of standardized criteria and concepts regarding the issue of antibiotic hypersensitivity leads to ambiguity in the diagnostic and therapeutic process, especially in out-of-hospital care where access to diagnostic facilities is limited. An important problem is the unjustified overdiagnosis of allergy to antibiotics, especially penicillins. In the vast majority of patients with a history of hypersensitivity reactions to beta-lactam antibiotics, this diagnosis was not confirmed after diagnostic testing. A rash associated with the use of antibiotics is not always an indication of an allergic reaction. It may be the result of factors unrelated to the antibiotic treatment, such as the presence of an underlying viral infection and the onset of a rash as part of the natural course of this infection. The misclassification of a patient as "allergic to antibiotic X" leads to the use of other, less preferred groups of antibiotics in given clinical situations, including those with a higher risk of adverse effects. Consequently, this also contributes to the growing problem of antibiotic resistance and increases the cost of patient care. A thorough and targeted medical history, including hypersensitivity reactions to drugs, especially antibiotics, together with an awareness of the available diagnostic and therapeutic options and knowledge of the specificity of different groups of antibiotics, allows the selection of a safe and effective treatment for each patient.