To explore the external curative effect of Rhizoma Bletillae rubbing agent in oral ulceration guinea pig's model with Shanghuo. Methods:The guinea pigs, whose right cheeks were burnt by 30% acetic acid to establish the models of oral ulceration. After successful modeling, the 25 guinea pigs were divided into model group, western medicine treatment group, Chinese medicine treatment group (Chinese medicine A group, Chinese medicine B group, Chinese medicine C group), each group with 5 guinea pigs. Rhizoma Bletillae rubbing agent was made by Rhizoma Bletillae powder, Radix Ampelopsis powder and Retinervus Luffae Fructus Concentrated decoction. Rhizoma Bletillae rubbing agent was used on the guinea pig oral ulcers for five days. Chinese medicine A group used Rhizoma Bletillae rubbing agent once a day, while Chinese medicine B group used Rhizoma Bletillae rubbing agent twice a day, and Chinese medicine C group used Rhizoma Bletillae rubbing agent three times a day. Western medicine treatment group used Chlortetracycline eye ointment on the guinea pig oral ulcers twice a day for five days. The model group was not given treatment. The blank group of 5 guinea pigs used the Rhizoma Bletillae rubbing agent once a day. The effects of different dosages of Rhizoma Bletillae rubbing agent on oral ulcer area changes, degrees and local histopathological changes in guinea pig oral ulcer model were observed. Results:The oral ulceration in guinea pig's model whose right cheeks were burnt by 30% acetic acid was successful. Compared with the model group, Rhizoma Bletillae rubbing agent can remarkably improve the area of ulceration and the pathological changes. Conclusion:Rhizoma Bletillae rubbing agent has remarkable external curative effect on oral ulceration guinea pig's model.