Marijuana smoking as a possible cause of tongue carcinoma in young patients. A case of T1N0M0 carcinoma of the tongue in a male 23-year-old 'regular' marijuana smoker is described. Hemiglossectomy and complete bilateral neck dissection were carried out. No post-operative radiotherapy was given as the resection margins were histologically negative. The tumour recurred one year later in the left cervical region involving the mandible and surgery was again performed, but after three months, neck disease was still evident. The case described case implies the introduction of marijuana as a possible new risk factor in the development of oral cavity tumours. Resection of the primary lesion has to be as wide as possible even in T1 cases, due to the aggressive biological behaviour of such tumours in young subjects. 