Facial cellulitis caused by odontogenic bacterial infection is frequently encountered; however, facial cellulitis caused by Candida albicans infection is rarely found. A patient with oral submucous fibrosis (OSF) and unknown diabetes mellitus (DM) was treated in our out-patient dental clinic by biweekly submucosal injection of 40 mg triamcinolone acetonide into bilateral buccal mucosae plus forced mouth opening performed by the two hands of the clinician. The interincisal distance of the patient improved from 28 to 48 mm after four times of steroid injection. The symptoms and signs of OSF also improved markedly. Unfortunately, facial candidal cellulitis occurred 2 months after the last time of steroid injection treatment. The infection was cured by incision and drainage, intravenous administration of amphotericin B (100 mg once a day for a week), and an appropriate medical control of DM. No recurrence of facial cellulitis was found during the follow-up period of 18 months. To prevent the occurrence of facial cellulitis after a high-dose steroid therapy, some prophylactic procedures should be taken before the initiation of the steroid treatment.