A 23 year-old male presented complaining of gingival pain of at least one month's duration. He had visited his dentist who applied conventional treatment of gingivitis, without however resolution of the gingival pain. Oral clinical examination revealed ulcers covered by necrotic pseudomembranes at the free and interdental gingivae, on both labial (fig. 1) and palatal aspects (fig. 2). The clinical diagnosis was necrotizing ulcerative gingivitis. Metronidazole per os and Daktarin oral gel were administered with a relatively good response. The general blood count was within normal limits. The predisposing factor for the lesion was considered as some kind of immunodeficiency and laboratory testing for the ratio of T4/T8 was found to be 0.4.