Oral ulcers are the most prevalent diseases of the oral cavity. Various factors may cause occurrence of such kinds of wounds, such as Physical and Chemical Trauma, Microbial infections, diseases or drug use, malignances and nonspecific causes. The aim of the present study is to determine the effect of Thymus caramanicus Jalas extract on healing Oral ulcers of white male rats. Present experimental clinical study was conducted on 48 adult male rats which were randomly divided into 3 groups of 16 rats, named Hydro-alcoholic extract, Essence and Control. On the first day of experiment a 2-millimeter wound was made by the application of a biopsy punch inside the mouth of each group. For the 1st group, the Hydro-alcoholic extract of T. caramanicus Jalas was used every 12 hours on a daily basis, for the 2nd group, the essence was used on the wound and, for the 3rd group, no drug was used. The progress of wounds healing was clinically examined on the 2nd, 4th, 6th and 8th days by the application of caliper, and histopathologic examination was conducted upon observation of the slides prepared. Data was analyzed by SPSS-21 software and ANOVA statistical test within the significance level of 0.05%. The results showed a significant decrease in the clinical size of the wound in extract group in comparison with control group on the 8th day. The average size of clinical ulcers on the 2nd day was similar in both groups. Furthermore, on the 6th and the 8th days, a significant decrease was observed in the size of the ulcers in extract group in comparison with the essence group (P<0.05). Results of the present study showed that the extract of T. caramanicus Jalas causes improvement in the process of the oral ulcers healing in the rats.