[Aim]  To elucidate the defensive substances, specifically tannins and flavonoids, released by Triadica sebifera in response to feeding damage inflicted by various herbivores. [Methods]  A field survey was conducted to document the types of damage inflicted by herbivores, and the rates of herbivory, on T. sebifera. Concentrations of tannins and flavonoids in the leaves and roots of T. sebifera were also determined. In a laboratory experiment, a single species of herbivore (either Cnidocampa flavescens, Bikasha collari or Heterapoderopsis bicallosicolli), or pairs of these species, were allowed to feed on T. sebifera plants and changes in the tannins and flavonoids in the leaves and roots of these plants were measured and compared. [Results]  The field survey indicated that an increase in the hole feeding rate (R²=0.053 7, P=0.015 9) and in the marginal feeding rate (R²=0.060 6, P=0.008 9) significantly elevated the tannin concentration in leaves, but not in roots (P>0.05). An increase in the marginal feeding rate, however, significantly raised the flavonoid concentration in both the leaves (R²=0.081 9, P=0.017 2) and the roots (R²=0.133 4, P=0.002 8). Marginal feeding was the most significant factor driving changes in leaf tannins (contribution rate: 8.3%, R²=0.134) and root flavonoids (contribution rate: 19.76%, R²=0.230). The results of laboratory experiments revealed that feeding by C. flavescens, B. collari or H. bicallosicolli significantly increased the tannin concentration in leaves but did not affect that in the roots. Feeding by C. flavescens significantly enhanced the flavonoid concentration in the leaves, whereas simultaneous feeding by C. flavescens and H. bicallosicolli significantly raised the flavonoid concentration in the roots. [Conclusion]  Feeding by above-ground herbivores induces different secondary metabolic responses in both the above-ground and below-ground parts of T. sebifera. Furthermore, feeding by different herbivores induced different secondary metabolic responses. Notably, when T. sebifera is fed upon by two species of herbivores, the induced secondary metabolic responses appear to be antagonistic towards one another.