The aim of this work was to evaluate chemical responses to biomass removal mimicking large herbivore action in Lupinus albus and Lupinus angustifolius aerial parts. GC and GC-MS were used to determine total alkaloid content (TAC) and alkaloid relative abundances in bitter and sweet varieties of each species. Bitter genotypes Vila vehla (Vv; 3.95 +/- 0.26 mg/g of DM) and El Harrach (EH; 3.99 +/- 0.19 mg/g of DM) showed after damage 22 and 32.8% TAC increases, respectively. Even sweet varieties, with very low alkaloid contents, Gungurru (Gu; 0.51 +/- 0.09 mg/g of DM) and Rumbo (Ru; 0.53 +/- 0.09 mg/g of DM) exhibited higher induced responses of 58.8 and 67.9%, respectively, and their final TAC values remained low, distinctly apart from those corresponding to bitter species. Moreover, minor components such as ammodendrine, reported to exhibit teratogenic potential, showed no significant changes in their relative abundances in response to biomass removal in these genotypes.