A 35-year-old woman with severe fistulizing Crohn's disease presented with pyostomatitis vegetans affecting both the mouth and the vulva. The coalescing pustules transformed within several days into vegetating lesions on areas of inflammation. Microbial assessments revealed no pathogenic agent. Histology showed neutrophilic microabscesses, but no granulomas. Three injections of infliximab and maintenance therapy with methotrexate resulted in rapid and complete regression of both the pyostomatitis vegetans and the Crohn's disease. Infliximab and methotrexate may be a promising treatment for the rare cases of pyostomatitis vegetans associated with Crohn's disease.