Introduction: Oral lichen planus (OLP) is a chronic immune-based muco-cutaneous disorder. Nutrition and eating [Nutrition pattern] might affect the exacerbation of symptoms. According to prevalence of OLP in Iran and lack of study on dietary pattern in Iranian OLP patients, we aimed to compare the dietary pattern in OLP patients and healthy subjects referred to dentistry faculty in Mashhad University of Medical Sciences [Mashhad faculty of dentistry], Iran. Materials and Methods: This case-control study was performed between October 2017 and March 2018 in the Oral and maxillofacial medicine department of dentistry faculty of Mashhad University of Medical Sciences [Mashhad faculty of dentistry], Iran. Patients with oral lichen planus lesions referred to our clinic included in the study. All subjects in healthy and OLP groups were assessed by dietary pattern of Food Frequency Questionnaire (FFQ). We used factor analysis for categorized food groups [pattern] in two categories. Data were entered in SPSS software version 20 and analyzed. Results: Totally, 106 subjects were entered in the study that 40 of them were in case group and 66 in control group. There were significant difference between two groups in vitamin E, folate, fast foods, dairy products, fruits, carbohydrate drinks, potato and coffee (P<0.05). We obtained two major food patterns. Odds of OLP in subjects with higher score in unhealthy food patterns was 27.6 times more than subjects in first one-third (reference) group (OR:27.6, CI 95%:2.9-262.9, P=0.004). Conclusion: Diet may affect the occurrence of OLP. Our results showed consumption of unhealthy food patterns increase the risk of oral lichen planus. It also demonstrated that there was significant difference in some food items in patients with OLP rather than [As compared to] healthy subjects.
