Angiogenesis is the process through which new blood vessels develop from an existing vascular system.It is closely related to ischemic diseases and abnormal vascular proliferation,making it a current research hotspot.Angiogenesis is a bidirectional regulatory process.On one hand,it relies on a precise balance between pro-angiogenic and anti-angiogenic factors.On the other hand,angiogenesis exerts both positive and negative regulatory effects on ischemic diseases and vascular proliferation disorders.The theory of yin and yang is one of the fundamental principles of traditional Chinese medicine(TCM),permeating the entire practice of syndrome differentiation and treatment.The bidirectional regulation of angiogenesis mirrors the yin-yang relationship,which embodies both opposition and unity,maintaining balance in angiogenesis.Key pathways involved in this bidirectional regulation include tumor necrosis factor-α(TNF-α),the Notch signaling pathway,the EphB4/Ephrin B2 signaling pathway,and the transforming growth factor-β(TGF-β)/Sma and Mad-related(Smad) signaling pathway,all of which align closely with the theory of yin-yang balance in maintaining angiogenic equilibrium.