Abstract: Objective To observation the changes of immune function in normal or tumor bearing animal after dose ZHEMU extract. Methods The carbon particle clearance test, macrophage phagocytosis test. NK cells activity and lymphocyte transformation in tumor bear animal are detected. Results The carbon granula clearance ability and phagocytosis of macrophage cell in abdominal on normal mice, and the lymphocyte transformation and natural killer (NK) cell activity in tumor bearing mice were enhanced after dosing, and the lowest effective dose were 0.3 g/kg, equivalent to the crude herb 5.46 g/kg, which was 1.3 times of clinical daily dose. Conclusions ZHEMU extract can restrain the growth of gastrointestinal tract tumors, and its mechanism may be related to the direct inhibition of the gastrointestinal tract cancerous cells growth and the improvement of the body's specific and non-specific immune function.

Key words: ZHEMU extract, Gastrointestinal tract tumors, Anti-tumor activity, Immune function