Objective To summarize the characteristics of Chinese medicine syndromes and evolution rule of acute gastrointestinal radiation injury by observing the dynamic changes of living animals

organs and tissues in experimental animals. Methods Ninety SD male rats were randomly divided into model group（n = 80） and control group（n = 10）. The model group was irradiated with a single dose of60 Co-γ radiation and the control group was not irradiated. The general condition of the rats was observed. The changes of gastrointestinal tract and histomorphology were observed with the naked eye and the microscope at 1

4

7

10

and 14 days after irradiation. Results In the initial post-irradiation period（0 to 2 days）

the model group showed signs of restlessness

excessive drinking

and red eyes. The small intestine mucosa was slightly congested and with edema. In the early stage（3 to 6 days）

body weight decreased with watery stools

and small intestine mucosal was with obvious congestion and edema

as well as multiple bleeding

erosion and necrosis. In the middle stage（7 to 12 days）

after a brief recovery

body weight continued to decline

and unwilling to eat

with massive death. Purple-black mucus was deposited in the gastrointestinal cavity

and submucosal microvascular was occluded. In late or early recovery stage（13 days later）

the rats were cowered with less activity

dry hair

pale paws

and increased interstitial fibers in the intestine. The control group had no abnormalities in living body

gastrointestinal and mucosal tissues. Conclusion Acute radiation damage of gastrointestinal tract is internal exuberance of heat toxin

blazing of both Qi and blood syndrome in the initial stage;heat burning flesh and blood

Yuan Qi consumption and damage

and devitalization of spleen Yang syndrome in the early stage; Yuan Qi deficiency and damage

true Yin consumption and damage

binding of blood stasis and toxin syndrome in the middle stage; and the liver and kidney depletion and consumption

Qi and blood deficiency

blood stasis and collateral obstruction syndrome in the late stage.