Objective: Through cell cultivation, we studied the inhibiting effects of the serum of the dog fed with Panax notoginseng extracts on precancerous gastric cells, trying to find the best time points or periods when the extracts' function was the strongest after administration of the extracts to the dog.Methods: The experiments adopted eternalized human gastric mucosa epithelium GES-1 cells and MC cells gained from GES-1 cells transformed by N-methyl-N'-nitro-N-nitroso-guanidine (MNNG) as the model of precancerous lesions for study in vitro. We took the serum of a dog before and at different points of time after feeding the dog with Panax notoginseng extracts for experiment. By means of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, we examined the inhibiting effects of the serum after culturing the GES-1 and MC cells for 72 hours with different concentration (8%, 4%, 2%) of medicated serum obtained from the dog at different points of time, so as to find that, at which points of time the medicated serum obtained, it would be the most effective.Results: The results showed that the GES-1 and MC cells inhibition rates of medicated serum from the points of 2-hour and 6-hour were the highest, and the culture medium containing 8% of medicated serum from these two points had prominent inhibiting effects on both kinds of cells. The GES-1 cells inhibition rate in culture medium containing 8% of medicated serum from the point of 2-hour was 70.8% (P<0.01) and that of the MC cells was 45.3% (P<0.01). The GES-1 cells inhibition rate in culture medium containing 8% of medicated serum from the point of 6-hour was 88.5% (P<0.01) and that of the MC cells was 42.4% (P<0.01).Conclusion: The points of time with the strongest inhibiting effects are 2 hours and 6 hours after being fed with Panax notoginseng extracts. At these two points, the serum is most effective in inhibiting the proliferation of GES-1 and MC cells.

Key words: Panax notoginseng, gastric cancer, cell culture, animals, laboratory