Background: Allergic rhinitis (AR) continues to increase in incidence and is the most common allergic disease. If abstention of the allergen triggering substances is not possible, allergen-specific immunotherapy (AIT) as causal treatment or a drug therapy with mast cell stabilizers, antihistamines (AHs), glucocorticoids (GCs), leukotriene (LT) receptor antagonists and decongestants is indicated. Despite these diverse therapeutic options, studies on the real-life care situation of patients with AR regularly show that a considerable proportion of patients do not feel adequately treated with monotherapy of the usual drugs and therefore use several preparations with different active ingredients simultaneously and in various combinations. However, such parallel applications of several active ingredients are normally not tested in approval studies and therefore carry a potential risk of side effects or lack of efficacy. Methods: For the present publication, a focused literature search in PubMed, Livivo and on the World Wide Web for the previous 20 years (period 01/1999 to 01/2020) was carried out. This literature search included original and review articles in German or English. A further analysis of current publications was also conducted for German-language journals that are not available in international literature databases. Results: AHs and nasal GCs represent the therapeutic standard in AR. Their efficacy is well documented for several preparations. The evidence for combination therapies is documented very well for a fixed combination of azelastine and fluticasone (MP29-02). For the simultaneous use of non-fixed combined monopreparations, only a few efficacy and safety studies based on modern evidence criteria exist. Conclusion: The free combination therapies of mast cell stabilizers, decongestants, AHs and nasal GCs, frequently used in the routine care of patients with AR, cannot be recommended because they are not evidence-based. Due to the fact that over-the-counter antiallergic drugs are not reimbursable in Germany, there is no medical supervision of the therapy. In addition, there are doubts about appropriate treatment, especially of patients with persistent rhinitis with severe symptoms, as these patients often use several preparations at the same time to alleviate their symptoms.