Background: The objective study was to evaluate the use and the effectiveness of hyperbaric oxygen therapy as an adjuvant therapy in 6 cases of descending necrotizing mediastinitis.Methods: This is a retrospective descriptive study, performed between 2010 and 2019. Hyperbaric oxygen therapy was indicated in difficult clinical management cases despite surgery and antibiotic therapy.Results: Six patients had oxygen therapy sessions in addition to antibiotic treatment and surgery. There was marked clinical and radiological improvement in 5 cases. Only one patient died in a septic shock.Conclusions: Hyperbaric oxygen therapy, as adjuvant therapy to surgery and antibiotic treatment, can increase survival and provide good clinical results.