在中医理论中，疾病的本质可以归结为阴阳失衡。为了准确治疗疾病，中医医生必须能够辨别出疾病的“虚”与“实”、“寒”与“热”这四种基本病理状态。这种辨证方法被称为八纲辨证，是中医临床实践中的核心原则之一。

首先，我们来谈谈“虚”和“实”的区分。简单来说，“虚”是指人体正气不足，机能衰退的状态；而“实”则相反，指的是邪气亢盛，功能过于旺盛的状态。例如，感冒咳嗽的患者如果咳嗽气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘