Abstract: In order to study the acute toxicity of all-trans retinoic acid（ATRA）and its anti-infection effect in mice, the maximum dosage was used in ATRA acute toxicity experiment, while the clinical symptoms of mice were recorded for 7 days. Then acute toxicity of ATRA was studied by autopsy and histopathology observation. The mice infection model was established by oral infection with Escherichia coli to study the anti-infection effect of ATRA by recording the clinical symptoms, autopsy lesions and organ index of infected mice for 7 days. The results showed that the mice had not abnormal response and pathological changes in autopsy and histopathological observation compared to the control group in the maximum dosage of ATRA（500 times of the clinical dosage in human）. The weight was also of insignificant difference compared to the control group. At the same time, the high dose of ATRA in mice to regain the weight was better than the low dose group before infection with Escherichia coli. Liver index, kidney index and spleen index by using ATRA were significantly different compared with control groups. ATRA had no acute toxicity in mice and was good for the growth of liver, kidney and spleen to improve the immunity and anti-infection effect, which can be used in clinical veterinary treatment and disease prevention and control.

Key words: ATRA, acute toxicity, anti-infection effect, mice, Escherichia coli