It is proposed that although allergic rhinitis manifests primarily in the nasal orifices， its root lies in deficiency of the lung and spleen and insecurity of the lung defensive qi， while deficiency of healthy qi with latent pathogen， triggering by external stimuli， and constraint of defensive yang constitute the key pathogenesis. The onset of disease is not caused solely by newly contracted external pathogens. Rather， on the basis of insecurity of the lung-defense qi， external stimuli such as wind-cold and abnormal qi， dust mites， pollen， and sudden climatic changes， activate the latent pathogen， resulting in constraint of defensive yang， disharmony between nutritive and defensive qi， impaired diffusion of lung qi， failure to contain body fluids， and dysfunction of the nasal orifices. The disease progression can be summarized as following steps， deficiency of healthy qi with latent pathogen， activation by external stimuli， constraint of defensive yang， dysfunction of the nasal orifices， incomplete elimination of the pathogen and incomplete recovery of healthy qi. The general therapeutic principle is to consolidate the defensive qi and vent the latent pathogen while regulating the lung and nasal orifices simultaneously. The empirical prescription Xingui Fangzhi Decoction （辛桂防芷汤） is used as the basic formula and modified dynamically according to the attack and remission stages. During the attack stage， treatment focuses on dispelling wind and cold， regulating defensive qi， and venting the latent pathogen； during the remission stage， it emphasizes supplementing qi， consolidating the defensive exterior， and reinforcing the spleen to resolve the latent pathogen.