This is a rare case of descending necrotising mediastinitis (DNM) that originated as an oropharyngeal infection, before spreading caudally to include all compartments of the mediastinum and the peritoneum beyond. The mediastinitis was treated early and aggressively with drainage, lavage and debridement in conjunction with broad-spectrum antimicrobial treatment. This case includes a right cervical incision, and a seldom needed surgical laparotomy approach to address the intra-abdominal involvement, and necessity of peritoneal washout. Following a prolonged Intesive Care Unit (ICU) stay and antibiotic course as well as other interventions detailed, the patient made a remarkable recovery and was discharged 101 days post presentation. This report goes on to discuss the rapidly evolving, life-threatening nature of DNM as well as providing an overview of possible management options, outlining how we think such cases should be approached and the clinical suspicion required in a deteriorating patient.