We describe an 88-year-old woman with gas-forming submental cellulitis in whom nonsteroidal antiinflammatory drug (NSAID)-induced gastric ulcer led to hemorrhagic shock during treatment of an odontogenic infection. Hemodynamic treatment had to take priority, and intensive treatment for inflammation could not be performed. This apparently led to the development of descending necrotizing mediastinitis. During the six days of hospitalization, she took a total of 6 tablets of loxoprofen sodium (60 mg) and 1 diclofenac sodium suppository (25 mg) for analgesia after treatment.<BR>Retrospectively, if decisive and aggressive treatment for inflammation had been performed earlier after hospitalization, inflammation may have resolved sooner. Our experience reconfirms that the initial treatment of odontogenic infection is extremely important in very elderly patients. Even if NSAIDs are received for a short period of time in small doses, gastrointestinal hemorrhage can occur, as in our patient. Patients at high risk for gastrointestinal ulcer should receive prophylactic treatment with cyclo-oxygenase 2 inhibitors orproton pump inhibitors.Generally, very elderly patients have a high risk of complications because of considerable age-related declines in physical ability and functional reserve of organs. Very cautious treatment is therefore necessary.