CHF used to alleviate cough and sputum production occur most frequently in the spring, CHF used to allevi-ate nasal discharge and congestion prevail in the winter, and CHF used to alleviate headaches and dizziness occur most frequently in the autumn and winter. The findings in this study not only verified the basic TCM theories pertaining to the six natural climatic factors that cause URIs throughout the four seasons but also can serve as a reference for the preparation of preventive strategies against URIs and the treatment of URIs in clinical practice of TCM.