Lamb was used to make braised sauce meat. The effects of possible precursors on the formation of norharman (9H-pyrido- [4,3-b] indole) and harman (1-methyl-9H-pyrido-[4,3-b] indole) in braised sauce meat were studied by adding different concentrations of tryptophan, phenylalanine, creatine and glucose. The results showed that the amounts of norharman and harman in braised sauce meat and soup were enhanced with increasing the levels of tryptophan. With addition of 2.4 mmol tryptophan, the total amounts of norharman and harman in both sauced meat and soup were 3.85 times and 2.33 times more than that in the blank control groups. Except with the concentration of 1.2 mmol, phenylalanine did not show any consistent effect of concentration on β-carboline. Creatine with low levels (eg. 0.12 mmol) had a strong influence on the formation of β-carboline in braised sauce meat and soup rather than high levels. The contents of norharman and harman increased and then decreased with the increasing of glucose. When adding1.2 mmol glucose, the total amounts of norharman and harman in sauced meat and soup increased by 54% and 66%, respectively.