In June, 2008, a 30-year-old Japanese man presented to our emergency department with a sore throat and fever. The previous day he had been to a local clinic and prescribed antibiotics and non-steroidal antiinfl ammatory drugs. However, treatment was ineff ective and his fever increased (up to 38·1°C). On admission, he was transferred to our otolaryngology department with possible diagnosis of acute parotitis. He had a fever (38·0°C), was hoarse, and had diffi culty speaking. His neck was very swollen with redness of the skin. There was no rash. We made a preliminary diagnosis of cervical abscess, rather than parotitis. Laryngeal fi broscopy showed pronounced oedema of the larynx, extending from the right arytenoid (cartilage around the larynx) to the right side of the root of the tongue. Enhanced CT of the neck showed that the right parotid and submandibular glands were very swollen, with no evidence of a cervical abscess (fi gure A). Laboratory tests showed leucocyte count of 5·1×109/L (neutrophils 48·0%, lymphocytes 32·0%, and monocytes 19·0%), serum amylase 562 IU/L, and CRP 34·4 g/L. These results suggested a viral rather than bacterial infection. We suspected that our patient had mumps, although there were no signs or symptoms of orchitis; history of mumps infection or mumps vaccination was not defi nitive. We gave the patient intravenous hydrocortisone (500 mg) immediately. His laryngeal oedema, fever, hoarseness, and neck swelling improved the next day. On day 4 of admission, swelling of his left parotid gland was noted, again supporting a diagnosis of mumps. The diagnosis was confi rmed by mumps virus antibody titres (IgM+, IgG±). The patient was discharged on day 8. When seen for fi nal follow-up in July, 2008, he was well with no complications. After the implementation of large-scale immunisation programmes, mumps is uncommon in many countries. Laryngeal oedema is a rarely reported complication of mumps. There is only one English-language paper from Japan reporting three cases of mumps-related laryngeal oedema. Seven other similar cases were reported in Japanese-language publications. All ten patients were Japanese adults and had submandibular gland swelling. It is well established that serious complications from mumps arise more often in adults than in children. Kimura and colleagues suggest that laryngeal oedema is caused by lymphatic congestion secondary to neck swelling by infl amed glands. The reason all the reported cases of laryngeal oedema secondary to mumps are from Japan only is presumably because of the high incidence of mumps there. The Ministry for Health, Labour, and Welfare of Japan estimated the number of mumps cases in Japan to be 2·26 million in 2001; only 226 cases were reported in the USA in the same year. In many countries, immunisation against mumps is incorporated in the vaccination schedule. In Japan incorporation into the schedule started in 1988 but was discontinued in 1993 because of several cases of aseptic meningitis. Within the Organisation for Economic Co-operation and Development, which comprises 30 member states, mumps immunisation schedule is routine in 28 countries, with Japan classifi ed as a “no mumps vaccine” state. To prevent serious complications associated with mumps in Japan, incorporating a safe mumps vaccine into the vaccination schedule should be reconsidered by the Japanese Government.