In this study, a pharmaceutical formula was prepared in form of mouth paste for the treatment of recurrent aphthous stomatitis by using alcoholic extract of Ruta Graveolens, which is known as Rue. The effectiveness of Rue paste 2nd formula contained in addition to the base, the active constituent (the alcoholic extract of Ruta Graveolens) and olive oil was studied in comparison with that of other two pastes prepared with the same general base of Rue paste except that: The 1st formula contains in addition to the base, the active constituent (the alcoholic extract of Ruta Graveolens) and sesame oil. The 3rd formula contains the general base prepared with olive oil as Rue paste, but it is free from the active constituent (the control base). The microbial and stability studies of these formulas indicated that they are free from any microorganism and they are stable related to their consistency, color, odor and taste, as well as pH except at 50 C temperature. The clinical studies done on l0l patients of both sexes showed that the rate of aphthous ulcer healing in most of the patients for the 1st group formula, and 2nd group formula was less than one week in a percentage of 65.79% and 88.89 % respectively, compared with 3.7 Vo of the placebo group, which indicate the clinical effect of the Rue. The size of ulcer decreased during the lst day of application of the formula in 42.11% of the patients for 1st group and 66.67% for 2nd group and 0.07% for placebo group. The pain intensity decreased in patients through the first 24 hours in 89.47% of the patients for the 1st group, 97.220 for the 2nd group and 29.63% for placebo group. Besides, the pain disappeared during the first five minutes of using the drug and its disappearance persists for more than four hours. From these results, it appears that Ruta Gravcolens herb contains effective compounds and its alcoholic extract is highly effective in the treatment of recurrent aphthous stomatitis. The Ruebase containing olive oil (2nd formula) seems to be more effective than the first one and it can be considered as a promising cheap and easily prepared medicinal formula for the treatment of recurrent oral aphthous ulceration.