Complementary-alternative medicines are extensively used in the treatment of allergic rhinitis and asthma, but evidence-based recommendations are lacking. To provide evidence-based recommendations, the literature was searched by using MedLine and the Cochrane Library to March 2005 (Key words: Asthma [OR] Rhinitis, [AND] Complementary [OR] Alternative Medicine, [OR] Herbal, [OR] Acupuncture, [OR] Homeopathy, [OR] Alternative Treatment). Randomized trials, preferably double-blind and published in English, were selected. The articles were evaluated by a panel of experts. Quality of reporting was assessed by using the scale validated by Jadad. The methodology of clinical trials with complementary-alternative medicine was frequently inadequate. Meta-analyses provided no clear evidence for the efficacy of acupuncture in rhinitis and asthma. Some positive results were described with homeopathy in good-quality trials in rhinitis, but a number of negative studies were also found. Therefore it is not possible to provide evidence-based recommendations for homeopathy in the treatment of allergic rhinitis, and further trials are needed. A limited number of studies of herbal remedies showed some efficacy in rhinitis and asthma, but the studies were too few to make recommendations. There are also unresolved safety concerns. Therapeutic efficacy of complementary-alternative treatments for rhinitis and asthma is not supported by currently available evidence.