Herbal interventions in asthma and allergy.

This paper reviews the role of herbal-based medicines in the treatment of asthma and allergic rhinitis. A comprehensive literature search was performed of relevant English-language papers and abstracts were identified through a MEDLINE search and from bibliographies of the identified papers. Papers and studies pertaining to the use of medicinal plants in the treatment of asthma and allergic rhinitis were identified. They were then analyzed according to design, inclusion and exclusion criteria, population studied, variables tested, method of treatment (i.e., specific medicinal plants or herbal combinations), and results. The data have been reviewed and divided on the basis of culture and the effects of medicinal plants in asthma and allergy. A number of studies were found that support the use of some herbal medicines in asthma and allergy. Various derivatives from specific medicinal plants were identified as the antiasthma components and some mechanisms of action were explored. The results show positive effects of these herbs on bronchodilation, pulmonary function tests, and antagonism of asthma mediators such as histamine and platelet activating factor, corticosteroid levels, and clearance of mucus. Improved symptoms were also seen in patients with allergic rhinitis specifically on histamine-induced reactions, e.g., rhinorrhea, sneezing, and itching. From the review, there has been a role for some herbal medicines in the treatment of asthma and allergic rhinitis. Usage of herbal medicines has increased in recent years. Many of these medicinal plants provided relief of symptoms equal to allopathic medicines used. Specific chemical derivatives have been isolated from many of these plant products which act on the mechanisms and mediators that cause asthma and allergies. The amount of research on these products, especially in the United States, is limited. There is a lack of control of quantity and quality of the components in these remedies. Yet, many have fewer side effects than current therapy. Throughout the history of medicine, drugs have been developed from traditional medicine. By continuing to investigate how some of these herbal interventions work, we may be able to find additional effective medicines to treat asthma and allergies.