The effects of pentagastrin (PG) on the viable cell count (Α value) and the synthesis of DNA (CPM value) of primary cultured large bowel carcinoma cells in 25 patients were evaluated in vitro by MTT assay,3H-TdR incorporation. The results showed that Α value and CPM value in well， moderately and poorly-differentiated carcinoma cells were higher than normal control (Ｐlt;0.01，Ｐ＜0.05). The proliferative effect was significant at a dose of 0.3907 μg/ml in well-differentiated carcinoma cells, and at a dose of 6.2500μg/ml in moderately and poorly-differentiated carcinoma cells. These indicat that PG has the proliferative effect on large bowel carcinoma cells. These results provide an experimental foundation for the endocrine therapy for patients with large intestine carcinoma, especially by using gastrin receptor antagonists for well-differentiated carcinoma.