Pemphigus vulgaris produces multiple and intractable erosions of the oral mucosa in the head and neck region. We describe a case of pemphigus vulgaris that showed erosions in the hypopharynx and stenosis of the esophageal orifice from an osteoporosis drug. A 73-year-old woman was admitted with oral intake difficulty and erosions in the hypopharynx. During the first admission, we could not make a definite diagnosis by biopsy or blood examination. The condition of the mucosa worsened subsequently; an esophagram showed marked stenosis of the esophageal orifice. As a possible factor exacerbating the stenosis, an osteoporosis drug was considered. The stenosis was improved by balloon expansion. One year after the first medical examination, we finally made a definite diagnosis of pemphigus vulgaris from the results of a blood examination in which anti-desmoglein 3 turned positive when the hypopharyngeal erosions and stenosis of the esophageal orifice became worse. Systemic treatment with a steroid was effective for the control of pemphigus vulgaris; restenosis of the esophageal orifice was recognized twice during a state of remission, and careful follow-up will be necessary in the future.