The tumorigenic effects of 2 L-glutamic acid pyrolysates to ICR mice were studied. The newborn animals received subcutaneously either 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) or 2-amino-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2). The mice were observed for 1 year. The tumors of the lung and liver were induced. Statistical analysis revealed that the incidences of the lung tumor in the mice given Glu-P-1 or Glu-P-2 and that of liver tumor in the male mice given Glu-P-2 25 mg/kg body wt were significantly higher than those of controls.