Herbal treatments of asthma: a systematic review.

BACKGROUND Asthma is a condition, often chronic, characterized by respiratory symptoms, variable airflow limitation and/or airway hyper-reactivity with symptoms causally related to family history, environmental influences, exposure to viruses and allergens as examples. The high economic burden associated with asthma is associated primarily with health care costs, missed work or school days. This systematic review was conducted to determine the study quality of articles investigating ayurvedic/collateral herbs, the effectiveness/efficacy and safety profile, as reported in the studies. METHODS Literature searches were conducted using PubMed, EMBASE, Mantis, Ovid, Annotated Bibliography of Indian Medicine, and Cochrane library to identify published trials on herbal medicines for asthma of which Ayruvedic herbals are a subset. Randomized Controlled Trials (RCTs) and Quasi-Experimental Designs (QEDs) were included in this systematic review. The classic Jadad Scale, Singh RCT Scale with additional domains than Jadad, Safety Scoring Scale for clinical trials and the Singh QED Scale based on expanded features of QEDs were used to assess study quality. Herbs included in Traditional Chinese Medicine were excluded from this review. Forty-two articles were retrieved and 37 studies were ultimately reviewed utilizing 3 independent evaluators/1 arbitrator. RESULTS Articles reviewed indicated benefit from most of the herbs used either as a primary or adjunctive treatment for Asthma. Study quality was mixed and therefore caution in interpretation of findings of usefulness of these herbals must be suggested. Limited safety information was mixed and generally was related to GI symptoms, though one herbal investigated reported more serious side effects. CONCLUSIONS Herbs may be useful in treatment of asthma. There is insufficient evidence to make recommendations for or against the use of these herbals. Established effectiveness must be balanced with study quality and safety profile for the herb.