Objective: To observe the effects of quercetin on the proliferation of 3AO cells. Methods: 3AO cell proliferation was evaluated by viable cell count. Alkaline phosphatase (ALP) activity was determined as described in reference 4. Results: Quercetin(1,10,20,40 mol/L) inhibited the proliferation of 3AO cells in a time and dosedependent manner. After treatment with quercetin (40 mol/L)for 1 d,the viable cell count is only 47.06% of control;after the removal of quercetin,the treated 3AO cells regrew l...