Abstract: Objective To observe the effect of FN in the treatment of mouth ulcer.Methods The patients(n=150) were randomly divided into FN group and control group.Results The reduction of ulce and congestion area of FN group were significantly greater than that of the control group（P＜0.05）. The degree of pain relief of spontaneous pain，burning pain and bowel pain were significantly greater than that of the control group（P＜0.05）.Conclusions FN treatment for mouth ulcer is effective and safe，and has great clinical value.

Key words: fibronectin, mouth ulcer, treatment