Abstract <p>Among numerous related natural proteins of plant and animal origin, there are families that can induce cross-IgE-mediated allergic reactions. Such protein families are called panallergens. Each family of panallegens has its specific physicochemical and immunobiological characteristics, which affect their allergenic properties. This review describes the main families of panallergens, their structure, properties, and functions and the possible consequences of patients sensitizations, as well as modern methods of molecular allergy diagnostics. The review provides a summary table of panallergen protein families. The choice of appropriate therapy of allergic pathologies, especially allergen-specific immunotherapy, and elimination measures largely depends on accurate and early diagnosis of allergic diseases. As with any pathology, the therapy of allergic diseases is effective only when it is pathogenetically justified, an integrated approach is applied, and the sequence of therapeutic measures is followed. Accordingly, understanding panallergen families and their properties allows clinicians to better identify cross-reactions and select targeted therapies for allergic patients.</p>