The present paper reviews the clinical research carried out over the past three decades to evaluate the effectiveness of homeopathy for the treatment of respiratory allergies, common upper respiratory tract infections, otorhinolaryngologic complaints, and rheumatic diseases. We include in the analysis both randomised and non-randomised trials, assigning them different weightings in the final balance of evidence, on the basis of semi-quantitative criteria. Overall, the literature concerning a total of 83 original studies suggests that homeopathy may have significant effects in some conditions, e.g. Galphimia glauca (low homeopathic dilutions/dynamizations) in allergic oculorhinitis, Anas barbariae (high homeopathic dilution/dynamization) in influenza-like syndromes, classical individualised homeopathy in otitis, in allergic complaints and in fibromyalgia, and a few low-potency homeopathic complexes in sinusitis, rhinoconjunctivitis, arthritis. The evidence for individualised homeopathic therapy in the field of upper respiratory tract infections and for homeopathic immunotherapy in respiratory allergies is more conflicting. Pragmatic equivalence trials suggest that, in primary care, homeopathic treatment is not inferior to conventional treatment. A larger number of observational studies and of clinical trials -- conducted in a methodologically correct manner without altering the treatment setting-- are needed before sure conclusions concerning the application of homeopathy for specific diseases can be drawn.