Betel nut (Areca catechu) is a widely chewed plant that is grown and eaten in Asia and the Pacific. Prolonged consumption of betel nut may lead to oral health problems such as oral mucosal damage and oral fibrosis. The aim of this review paper is to examine the current state of research on the effects of betel nut on oral mucosal health, particularly in relation to oral injury and oral fibrosis.