Introduction:Oral ulcers form a category of the most commonly encountered oral lesions. It contains a wide variety that ranges from completely benign and self-limiting types to fatal and malignant types. Each of these types has different clinical presentation and an impact on all aspects of life. Hence, the current study aims to determine the prevalence of oral ulcers in adult patients visiting oral diagnosis clinic in faculty of Oral and Dental Medicine, Cairo University. It also aims to estimate the impact of oral ulcers on Quality of Life (QoL) and to report different used treatment options for oral ulcers and their effectiveness.Methods:This aim was achieved through a cross-sectional study using a questionnaire that was filled to 605 adult patients attending oral diagnosis clinic in faculty of oral and dental medicine, Cairo University. Then clinical examination was performed. If an oral ulcer was detected, the other questionnaire sections were filled. The other sections include OHIP-14 to detect impact of the oral ulcer on OHRQoL, types of previously used therapies and its effectiveness, number and specialties of previously visited clinicians.Results: Results showed that prevalence of oral ulcers in the participants was 10.3%, half of them had RAS. 59.7% of the oral ulcer patients were referred from other clinicians; 40.5% of which were not indicated for referral. Percentage of misdiagnosis was 53.8% from the previously diagnosed patients and undiagnosed cases were 78.4% from the referred cases. The high percentages of misdiagnosed, undiagnosed and unnecessarily referred patients reflect the poor efficiency of undergraduate Oral Medicine education and training.Oral ulcers proved to impact OHRQoL greatly. The highest impact was attributed to Erythema Multiforme followed by Pemphigus Vulgaris; while recurrent viral ulcers have the least impact on OHRQoL.From all oral ulcer patients, 85.5% used previous treatment; 66% of whom received incorrect treatment. The most commonly used treatment options were topical analgesics followed by non-conventional treatments. Unless for systemic steroids and vitamin supplements, all other treatment options proved no or minimal improvement in OHRQoL and in ulcer-free period.Regarding non-conventional treatments, the most frequently used was Tehini followed by a wide variety of natural ingredients.Oral ulcer patients visit a mean number of clinicians of 2.93±2.08 before reaching an Oral Medicine specialist. The number of visited clinicians is positively correlated to the impact of the oral ulcer on functional limitation, physical pain and psychological disability.