OBJECTIVEThis review focuses on current knowledge of traditional Chinese herbs on prevention and treatment of viral respiratory infections, especially caused by Severe Acute Respiratory Syndromes (SARS) virus, respiratory syncytial virus (RSV) and influenza viruses.

DATA SOURCESThe data used in this review were obtained from PubMed and CNKI up to May 2013. Terms of Chinese herbs and infections of respiratory tract were used in the search.

STUDY SELECTIONArticles related that Chinese herbs preventing and treating infections in respiratory tract were retrieved and reviewed. The risk of bias of included studies was assessed by the method in the "Cochrane Handbook of Systematic Reveiws of Interventionsand studies" with high risk of bias were excluded. Four criteria for selections were set as following: randomized controlled trial, particular effective compound or derivative, reproducible result and animal test.

RESULTSInfectious respiratory tract diseases cause most mortality among infectious illnesses around the world. As traditional medicines, Chinese herbs have been widely used to deal with diseases for centuries and have been proved effective in practice. The administration of some Chinese herbs stimulates, suppresses or regulates the activity of immune system, thus protecting the respiratory tract or relieving infections of pathogens. Many herbs have remarkable antiviral effects, therefore they are used as substitutes of antimicrobial drugs. Based on the theory of traditional Chinese medicine, mix-using herbs provide a synergistic benefit on preventing and healing respiratory tract infections. Many commercial herbal medicines containing one or more compounds have been successfully applied to prevent and treat viral infections of respiratory tract clinically.

CONCLUSIONSTraditional Chinese herbs could directly inhibit pathogens infecting respiratory tract, or coordinate the activity of immune system to avoid or relieve infections. With the emergence of antidrug pathogens or new variants, Chinese herbs give strong evidence to protect human health.