Neck mass is a common condition in primary care. The most common affected area is the cervical lymph node. The neck region is also prone infection as structurally the nodes and spaces are in close contact with the upper respiratory tract and the alimentary tract. Oral cavity is one of the most common route for harbouring infection. Poor oral hygeine and periapical dental problems are the main causes. Thus, it is important to perform a complete oral cavity examination even when trismus is present. Besides dental caries, floor of the mouth should be inspected for oedema that may impose threat to the upper airway. We report a case of Ludwig's angina originating from a periapical lesion of the lower molar stressing the importance of oral examination in patient with neck mass.