The oral cavity consists of the lips, teeth, gums, oral mucous membrane, palate, tongue and oral lymphoid system. The oral cavity plays an essential role in many key bodily functions, including nutrition (mastication and swallowing), respiration and communication. Various specialists may be called upon to diagnose and treat diseases of the oral cavity, including general practitioners, oral surgeons, otolaryngologists and others. The most important diagnostic tools for the examination of the mouth are the examiner‘s eyes aided by source of illumination, a tongue depressor and the use of palpation by the examiner‘s glove covered fingers. Whilst most diseases of oral cavity can be diagnosed by visual inspection, some disorders may be perplexing and their diagnoses may be elusive. Many disease processes, benign or malignant, localized or systemic, may present as an ulcerative lesion in the oral cavity. The list of possible diseases that may present as an ulcerative lesion in the oral cavity is quite extensive. The focus here will be on the most common causes of these lesions. Included are acute and chronic processes, benign and malignant diseases, generalized and systemic manifestations of ulcerative lesions in the oral cavity. The study is an attempt to enumerate the aetiopathological factors contributing to oral and oropharyngeal lesions.