Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 11 2 2014 04 15 167 71 Katayoun Borhan-Mojabi Associate Professor, Dental Caries Prevention Research Center, Qazvin University of Medical Sciences, Qazvin, Iran. Faezeh Mirmiran Assistant Professor, Dental Caries Prevention Research Center, Qazvin University of Medical Sciences, Qazvin, Iran. Marjan Nassiri-Asl Associate Professor of Pharmacology, Department of Pharmacology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran. Pantea Nazeman Dentist, Research Center, School of Dentistry, Qazvin University of Medical Sciences, Qazvin, Iran. Hassan Jahanihashemi Associate Professor of Biostatistics, Department of Biostatistics, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran. 2015 10 16 Recurrent aphthous stomatitis (RAS) is the most common and painful oral inflammatory lesion with an unknown etiology. This study aims to determine the therapeutic effects of ibuprofen, diphenhydramine and aluminum magnesium simethicone (AlMgS) syrup on reducing oral aphthous ulcer pain.Thirty-one patients with RAS participated in this double-blind clinical trial. Subjects were randomly divided into two groups. The control group (n=14) received drug mixture as drug A (diphenhydramine and AlMgS) and the case group (n=17) received drug B (ibuprofen, diphenhydramine and AlMgS). Drugs were topically applied on ulcers by the patients three times a day for 3 days. Patients were re-examined for the symptoms on the fourth day following their first visits using VAS (Visual Analogue Scale) tool. Statistical analysis was performed using paired t-test, independent t-test and chi-square test.The mean of pain reduction was 3.17±2 (P https://fid.tums.ac.ir/index.php/fid/article/view/527 https://fid.tums.ac.ir/index.php/fid/article/download/527/503